Remove OptimizationGuideUKM logging from PreviewsUKMObserver

Code to even log this from Previews land was removed in M79

Change-Id: I649467f73f909f73cba940f32710196ab2807023
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1988852Reviewed-by: Robert Ogden <robertogden@chromium.org>
Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Commit-Queue: Sophie Chang <sophiechang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728690}

chrome/browser/page_load_metrics/observers/previews_ukm_observer.cc

@@ -4,7 +4,6 @@
 
 #include "chrome/browser/page_load_metrics/observers/previews_ukm_observer.h"
 
-#include "base/base64.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/optional.h"
@@ -18,7 +17,6 @@
 #include "chrome/browser/profiles/profile.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h"
 #include "components/offline_pages/buildflags/buildflags.h"
-#include "components/optimization_guide/proto/hints.pb.h"
 #include "components/page_load_metrics/browser/page_load_metrics_observer.h"
 #include "components/page_load_metrics/browser/page_load_metrics_util.h"
 #include "components/page_load_metrics/common/page_load_timing.h"
@@ -144,9 +142,6 @@ PreviewsUKMObserver::OnCommit(content::NavigationHandle* navigation_handle,
   offline_eligibility_reason_ = previews_user_data->EligibilityReasonForPreview(
       previews::PreviewsType::OFFLINE);
 
-  serialized_hint_version_string_ =
-      previews_user_data->serialized_hint_version_string();
-
   return CONTINUE_OBSERVING;
 }
 
@@ -174,7 +169,7 @@ page_load_metrics::PageLoadMetricsObserver::ObservePolicy
 PreviewsUKMObserver::FlushMetricsOnAppEnterBackground(
     const page_load_metrics::mojom::PageLoadTiming& timing) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  RecordMetrics();
+  RecordPreviewsTypes();
   return STOP_OBSERVING;
 }
 
@@ -182,19 +177,14 @@ page_load_metrics::PageLoadMetricsObserver::ObservePolicy
 PreviewsUKMObserver::OnHidden(
     const page_load_metrics::mojom::PageLoadTiming& timing) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  RecordMetrics();
+  RecordPreviewsTypes();
   return STOP_OBSERVING;
 }
 
 void PreviewsUKMObserver::OnComplete(
     const page_load_metrics::mojom::PageLoadTiming& timing) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  RecordMetrics();
-}
-
-void PreviewsUKMObserver::RecordMetrics() {
   RecordPreviewsTypes();
-  RecordOptimizationGuideInfo();
 }
 
 void PreviewsUKMObserver::RecordPreviewsTypes() {
@@ -281,35 +271,6 @@ void PreviewsUKMObserver::RecordPreviewsTypes() {
   builder.Record(ukm::UkmRecorder::Get());
 }
 
-void PreviewsUKMObserver::RecordOptimizationGuideInfo() {
-  if (!serialized_hint_version_string_.has_value()) {
-    return;
-  }
-
-  // Deserialize the serialized version string into its protobuffer.
-  std::string binary_version_pb;
-  if (!base::Base64Decode(serialized_hint_version_string_.value(),
-                          &binary_version_pb))
-    return;
-
-  optimization_guide::proto::Version hint_version;
-  if (!hint_version.ParseFromString(binary_version_pb))
-    return;
-
-  ukm::builders::OptimizationGuide builder(GetDelegate().GetSourceId());
-  if (hint_version.has_generation_timestamp() &&
-      hint_version.generation_timestamp().seconds() > 0) {
-    builder.SetHintGenerationTimestamp(
-        hint_version.generation_timestamp().seconds());
-  }
-  if (hint_version.has_hint_source() &&
-      hint_version.hint_source() !=
-          optimization_guide::proto::HINT_SOURCE_UNKNOWN) {
-    builder.SetHintSource(static_cast<int>(hint_version.hint_source()));
-  }
-  builder.Record(ukm::UkmRecorder::Get());
-}
-
 void PreviewsUKMObserver::OnEventOccurred(const void* const event_key) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   if (event_key == PreviewsUITabHelper::OptOutEventKey())

chrome/browser/page_load_metrics/observers/previews_ukm_observer.h

@@ -55,9 +55,7 @@ class PreviewsUKMObserver : public page_load_metrics::PageLoadMetricsObserver {
   virtual bool IsOfflinePreview(content::WebContents* web_contents) const;
 
  private:
-  void RecordMetrics();
   void RecordPreviewsTypes();
-  void RecordOptimizationGuideInfo();
 
   // The preview type that was actually committed and seen by the user.
   PreviewsType committed_preview_;
@@ -85,7 +83,6 @@ class PreviewsUKMObserver : public page_load_metrics::PageLoadMetricsObserver {
   base::Optional<previews::PreviewsEligibilityReason>
       offline_eligibility_reason_;
   base::Optional<base::TimeDelta> navigation_restart_penalty_;
-  base::Optional<std::string> serialized_hint_version_string_;
 
   SEQUENCE_CHECKER(sequence_checker_);
 

chrome/browser/page_load_metrics/observers/previews_ukm_observer_unittest.cc

@@ -50,15 +50,13 @@ class TestPreviewsUKMObserver : public PreviewsUKMObserver {
       bool save_data_enabled,
       std::unordered_map<PreviewsType, PreviewsEligibilityReason>
           eligibility_reasons,
-      base::Optional<base::TimeDelta> navigation_restart_penalty,
-      base::Optional<std::string> hint_version_string)
+      base::Optional<base::TimeDelta> navigation_restart_penalty)
       : committed_state_(committed_state),
         allowed_state_(allowed_state),
         origin_opt_out_received_(origin_opt_out_received),
         save_data_enabled_(save_data_enabled),
         eligibility_reasons_(eligibility_reasons),
-        navigation_restart_penalty_(navigation_restart_penalty),
-        hint_version_string_(hint_version_string) {}
+        navigation_restart_penalty_(navigation_restart_penalty) {}
 
   ~TestPreviewsUKMObserver() override {}
 
@@ -93,11 +91,6 @@ class TestPreviewsUKMObserver : public PreviewsUKMObserver {
       user_data->SetEligibilityReasonForPreview(iter->first, iter->second);
     }
 
-    if (hint_version_string_.has_value()) {
-      user_data->set_serialized_hint_version_string(
-          hint_version_string_.value());
-    }
-
     return PreviewsUKMObserver::OnCommit(navigation_handle, source_id);
   }
 
@@ -118,7 +111,6 @@ class TestPreviewsUKMObserver : public PreviewsUKMObserver {
   std::unordered_map<PreviewsType, PreviewsEligibilityReason>
       eligibility_reasons_;
   base::Optional<base::TimeDelta> navigation_restart_penalty_;
-  base::Optional<std::string> hint_version_string_;
 
   DISALLOW_COPY_AND_ASSIGN(TestPreviewsUKMObserver);
 };
@@ -135,15 +127,13 @@ class PreviewsUKMObserverTest
                bool save_data_enabled,
                std::unordered_map<PreviewsType, PreviewsEligibilityReason>
                    eligibility_reasons,
-               base::Optional<base::TimeDelta> navigation_restart_penalty,
-               base::Optional<std::string> hint_version_string) {
+               base::Optional<base::TimeDelta> navigation_restart_penalty) {
     committed_state_ = committed_state;
     allowed_state_ = allowed_state;
     origin_opt_out_ = origin_opt_out;
     save_data_enabled_ = save_data_enabled;
     eligibility_reasons_ = eligibility_reasons;
     navigation_restart_penalty_ = navigation_restart_penalty;
-    hint_version_string_ = hint_version_string;
     auto navigation = content::NavigationSimulator::CreateBrowserInitiated(
         GURL(kDefaultTestUrl), web_contents());
     if (committed_state == content::OFFLINE_PAGE_ON)
@@ -152,44 +142,6 @@ class PreviewsUKMObserverTest
     navigation->Commit();
   }
 
-  void ValidateUKM(content::PreviewsState expected_recorded_previews,
-                   int opt_out_value,
-                   bool origin_opt_out_expected,
-                   bool save_data_enabled_expected,
-                   bool previews_likely_expected,
-                   std::unordered_map<PreviewsType, PreviewsEligibilityReason>
-                       eligibility_reasons,
-                   base::Optional<base::TimeDelta> navigation_restart_penalty,
-                   base::Optional<int64_t> hint_generation_timestamp,
-                   base::Optional<int> hint_source) {
-    ValidatePreviewsUKM(expected_recorded_previews, opt_out_value,
-                        origin_opt_out_expected, save_data_enabled_expected,
-                        previews_likely_expected, eligibility_reasons,
-                        navigation_restart_penalty);
-    ValidateOptimizationGuideUKM(hint_generation_timestamp, hint_source);
-  }
-
-  void SetUp() override {
-    page_load_metrics::PageLoadMetricsObserverTestHarness::SetUp();
-    PreviewsUITabHelper::CreateForWebContents(web_contents());
-  }
-
- protected:
-  void RegisterObservers(page_load_metrics::PageLoadTracker* tracker) override {
-    tracker->AddObserver(std::make_unique<TestPreviewsUKMObserver>(
-        committed_state_, allowed_state_, origin_opt_out_, save_data_enabled_,
-        eligibility_reasons_, navigation_restart_penalty_,
-        hint_version_string_));
-    // Data is only added to the first navigation after RunTest().
-    committed_state_ = content::PREVIEWS_OFF;
-    allowed_state_ = content::PREVIEWS_OFF;
-    origin_opt_out_ = false;
-    eligibility_reasons_.clear();
-    navigation_restart_penalty_ = base::nullopt;
-    hint_version_string_ = base::nullopt;
-  }
-
- private:
   void ValidatePreviewsUKM(
       content::PreviewsState expected_recorded_previews,
       int opt_out_value,
@@ -315,39 +267,25 @@ class PreviewsUKMObserverTest
     }
   }
 
-  void ValidateOptimizationGuideUKM(
-      base::Optional<int64_t> hint_generation_timestamp,
-      base::Optional<int> hint_source) {
-    using UkmEntry = ukm::builders::OptimizationGuide;
-    auto entries =
-        tester()->test_ukm_recorder().GetEntriesByName(UkmEntry::kEntryName);
-    if (!hint_generation_timestamp.has_value() && !hint_source.has_value()) {
-      EXPECT_EQ(0u, entries.size());
-      return;
-    }
+  void SetUp() override {
+    page_load_metrics::PageLoadMetricsObserverTestHarness::SetUp();
+    PreviewsUITabHelper::CreateForWebContents(web_contents());
+  }
 
-    EXPECT_EQ(1u, entries.size());
-    for (const auto* const entry : entries) {
-      tester()->test_ukm_recorder().ExpectEntrySourceHasUrl(
-          entry, GURL(kDefaultTestUrl));
-      if (hint_generation_timestamp.has_value()) {
-        tester()->test_ukm_recorder().ExpectEntryMetric(
-            entry, UkmEntry::kHintGenerationTimestampName,
-            hint_generation_timestamp.value());
-      } else {
-        EXPECT_FALSE(tester()->test_ukm_recorder().EntryHasMetric(
-            entry, UkmEntry::kHintGenerationTimestampName));
-      }
-      if (hint_source.has_value()) {
-        tester()->test_ukm_recorder().ExpectEntryMetric(
-            entry, UkmEntry::kHintSourceName, hint_source.value());
-      } else {
-        EXPECT_FALSE(tester()->test_ukm_recorder().EntryHasMetric(
-            entry, UkmEntry::kHintSourceName));
-      }
-    }
+ protected:
+  void RegisterObservers(page_load_metrics::PageLoadTracker* tracker) override {
+    tracker->AddObserver(std::make_unique<TestPreviewsUKMObserver>(
+        committed_state_, allowed_state_, origin_opt_out_, save_data_enabled_,
+        eligibility_reasons_, navigation_restart_penalty_));
+    // Data is only added to the first navigation after RunTest().
+    committed_state_ = content::PREVIEWS_OFF;
+    allowed_state_ = content::PREVIEWS_OFF;
+    origin_opt_out_ = false;
+    eligibility_reasons_.clear();
+    navigation_restart_penalty_ = base::nullopt;
   }
 
+ private:
   content::PreviewsState committed_state_ = content::PREVIEWS_OFF;
   content::PreviewsState allowed_state_ = content::PREVIEWS_OFF;
   bool origin_opt_out_ = false;
@@ -355,7 +293,6 @@ class PreviewsUKMObserverTest
   std::unordered_map<PreviewsType, PreviewsEligibilityReason>
       eligibility_reasons_ = {};
   base::Optional<base::TimeDelta> navigation_restart_penalty_ = base::nullopt;
-  base::Optional<std::string> hint_version_string_ = base::nullopt;
 
   DISALLOW_COPY_AND_ASSIGN(PreviewsUKMObserverTest);
 };
@@ -365,17 +302,14 @@ TEST_F(PreviewsUKMObserverTest, NoPreviewSeen) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, UntrackedPreviewTypeOptOut) {
@@ -383,20 +317,17 @@ TEST_F(PreviewsUKMObserverTest, UntrackedPreviewTypeOptOut) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
   tester()->metrics_web_contents_observer()->BroadcastEventToObservers(
       PreviewsUITabHelper::OptOutEventKey());
   tester()->NavigateToUntrackedUrl();
 
   // Opt out should not be added since we don't track this type.
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, LitePageSeen) {
@@ -405,18 +336,15 @@ TEST_F(PreviewsUKMObserverTest, LitePageSeen) {
               content::DEFER_ALL_SCRIPT_ON /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::SERVER_LITE_PAGE_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::SERVER_LITE_PAGE_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, LitePageOptOutChip) {
@@ -424,20 +352,17 @@ TEST_F(PreviewsUKMObserverTest, LitePageOptOutChip) {
           content::SERVER_LITE_PAGE_ON /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->metrics_web_contents_observer()->BroadcastEventToObservers(
       PreviewsUITabHelper::OptOutEventKey());
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::SERVER_LITE_PAGE_ON, 2 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::SERVER_LITE_PAGE_ON, 2 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, LitePageRedirectSeen) {
@@ -446,18 +371,15 @@ TEST_F(PreviewsUKMObserverTest, LitePageRedirectSeen) {
               content::OFFLINE_PAGE_ON /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::LITE_PAGE_REDIRECT_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::LITE_PAGE_REDIRECT_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, LitePageRedirectOptOutChip) {
@@ -465,37 +387,17 @@ TEST_F(PreviewsUKMObserverTest, LitePageRedirectOptOutChip) {
           content::LITE_PAGE_REDIRECT_ON /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->metrics_web_contents_observer()->BroadcastEventToObservers(
       PreviewsUITabHelper::OptOutEventKey());
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::LITE_PAGE_REDIRECT_ON, 2 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
-}
-
-TEST_F(PreviewsUKMObserverTest, NoScriptSeenWithBadVersionString) {
-  RunTest(content::NOSCRIPT_ON /* committed_state */,
-          content::NOSCRIPT_ON /* allowed_state */, false /* origin_opt_out */,
-          false /* save_data_enabled */, {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */, "badversion");
-
-  tester()->NavigateToUntrackedUrl();
-
-  ValidateUKM(content::NOSCRIPT_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::LITE_PAGE_REDIRECT_ON, 2 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, NoScriptOptOutChip) {
@@ -503,20 +405,17 @@ TEST_F(PreviewsUKMObserverTest, NoScriptOptOutChip) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->metrics_web_contents_observer()->BroadcastEventToObservers(
       PreviewsUITabHelper::OptOutEventKey());
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::NOSCRIPT_ON, 2 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::NOSCRIPT_ON, 2 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, OfflinePreviewsSeen) {
@@ -524,18 +423,15 @@ TEST_F(PreviewsUKMObserverTest, OfflinePreviewsSeen) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, ResourceLoadingHintsSeen) {
@@ -543,18 +439,15 @@ TEST_F(PreviewsUKMObserverTest, ResourceLoadingHintsSeen) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::RESOURCE_LOADING_HINTS_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::RESOURCE_LOADING_HINTS_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, ResourceLoadingHintsOptOutChip) {
@@ -562,20 +455,17 @@ TEST_F(PreviewsUKMObserverTest, ResourceLoadingHintsOptOutChip) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->metrics_web_contents_observer()->BroadcastEventToObservers(
       PreviewsUITabHelper::OptOutEventKey());
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::RESOURCE_LOADING_HINTS_ON, 2 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::RESOURCE_LOADING_HINTS_ON, 2 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, DeferAllScriptSeen) {
@@ -583,18 +473,15 @@ TEST_F(PreviewsUKMObserverTest, DeferAllScriptSeen) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::DEFER_ALL_SCRIPT_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::DEFER_ALL_SCRIPT_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, DeferAllScriptOptOutChip) {
@@ -602,20 +489,17 @@ TEST_F(PreviewsUKMObserverTest, DeferAllScriptOptOutChip) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->metrics_web_contents_observer()->BroadcastEventToObservers(
       PreviewsUITabHelper::OptOutEventKey());
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::DEFER_ALL_SCRIPT_ON, 2 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              true /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::DEFER_ALL_SCRIPT_ON, 2 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, OriginOptOut) {
@@ -623,18 +507,15 @@ TEST_F(PreviewsUKMObserverTest, OriginOptOut) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           true /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              true /* origin_opt_out_expected */,
-              false /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      true /* origin_opt_out_expected */,
+                      false /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, DataSaverEnabled) {
@@ -642,18 +523,15 @@ TEST_F(PreviewsUKMObserverTest, DataSaverEnabled) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, true /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 // Navigation restart penalty can occur independently of a preview being
@@ -664,19 +542,16 @@ TEST_F(PreviewsUKMObserverTest, NavigationRestartPenaltySeen) {
       content::PREVIEWS_UNSPECIFIED /* allowed_state */,
       false /* origin_opt_out */, false /* save_data_enabled */,
       {} /* eligibility_reasons */,
-      base::TimeDelta::FromMilliseconds(1337) /* navigation_restart_penalty */,
-      base::nullopt /* hint_version_string */);
+      base::TimeDelta::FromMilliseconds(1337) /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(
+  ValidatePreviewsUKM(
       content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
       false /* origin_opt_out_expected */,
       false /* save_data_enabled_expected */, false /* previews_likely */,
       {} /* eligibility_reasons */,
-      base::TimeDelta::FromMilliseconds(1337) /* navigation_restart_penalty */,
-      base::nullopt /* hint_generation_timestamp */,
-      base::nullopt /* hint_source */);
+      base::TimeDelta::FromMilliseconds(1337) /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, PreviewsLikelySet_PreCommitDecision) {
@@ -684,54 +559,45 @@ TEST_F(PreviewsUKMObserverTest, PreviewsLikelySet_PreCommitDecision) {
           content::OFFLINE_PAGE_ON | content::NOSCRIPT_ON /* allowed_state */,
           false /* origin_opt_out */, true /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */, true /* previews_likely */,
-              {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, PreviewsLikelyNotSet_PostCommitDecision) {
   RunTest(content::PREVIEWS_OFF /* committed_state */,
           content::NOSCRIPT_ON /* allowed_state */, false /* origin_opt_out */,
           true /* save_data_enabled */, {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, PreviewsLikelyNotSet_PreviewsOff) {
   RunTest(content::PREVIEWS_OFF /* committed_state */,
           content::PREVIEWS_OFF /* allowed_state */, false /* origin_opt_out */,
           true /* save_data_enabled */, {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, CoinFlipResult_Holdback) {
@@ -739,18 +605,15 @@ TEST_F(PreviewsUKMObserverTest, CoinFlipResult_Holdback) {
           content::OFFLINE_PAGE_ON /* allowed_state */,
           false /* origin_opt_out */, true /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */, true /* previews_likely */,
-              {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, CoinFlipResult_Allowed) {
@@ -758,18 +621,15 @@ TEST_F(PreviewsUKMObserverTest, CoinFlipResult_Allowed) {
           content::OFFLINE_PAGE_ON /* allowed_state */,
           false /* origin_opt_out */, true /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */, true /* previews_likely */,
-              {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::OFFLINE_PAGE_ON, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      true /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, LogPreviewsEligibilityReason_WithAllowed) {
@@ -786,25 +646,22 @@ TEST_F(PreviewsUKMObserverTest, LogPreviewsEligibilityReason_WithAllowed) {
            // ALLOWED is equal to zero and should not be recorded.
            {PreviewsType::LITE_PAGE_REDIRECT,
             PreviewsEligibilityReason::ALLOWED}} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */,
-              {{PreviewsType::OFFLINE,
-                PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
-               {PreviewsType::LITE_PAGE,
-                PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
-               {PreviewsType::NOSCRIPT,
-                PreviewsEligibilityReason::
-                    BLACKLIST_DATA_NOT_LOADED}} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(
+      content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+      false /* origin_opt_out_expected */,
+      true /* save_data_enabled_expected */, false /* previews_likely */,
+      {{PreviewsType::OFFLINE,
+        PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
+       {PreviewsType::LITE_PAGE,
+        PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
+       {PreviewsType::NOSCRIPT,
+        PreviewsEligibilityReason::
+            BLACKLIST_DATA_NOT_LOADED}} /* eligibility_reasons */,
+      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, LogPreviewsEligibilityReason_NoneAllowed) {
@@ -821,94 +678,24 @@ TEST_F(PreviewsUKMObserverTest, LogPreviewsEligibilityReason_NoneAllowed) {
            {PreviewsType::LITE_PAGE_REDIRECT,
             PreviewsEligibilityReason::
                 BLACKLIST_DATA_NOT_LOADED}} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
-
-  tester()->NavigateToUntrackedUrl();
-
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */,
-              {{PreviewsType::OFFLINE,
-                PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
-               {PreviewsType::LITE_PAGE,
-                PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
-               {PreviewsType::NOSCRIPT,
-                PreviewsEligibilityReason::BLACKLIST_DATA_NOT_LOADED},
-               {PreviewsType::LITE_PAGE_REDIRECT,
-                PreviewsEligibilityReason::
-                    BLACKLIST_DATA_NOT_LOADED}} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
-}
-
-TEST_F(PreviewsUKMObserverTest, LogOptimizationGuideHintVersion_NoHintSource) {
-  optimization_guide::proto::Version hint_version;
-  hint_version.mutable_generation_timestamp()->set_seconds(123);
-  std::string hint_version_string;
-  hint_version.SerializeToString(&hint_version_string);
-  base::Base64Encode(hint_version_string, &hint_version_string);
-  RunTest(content::PREVIEWS_OFF /* committed_state */,
-          content::PREVIEWS_UNSPECIFIED /* allowed_state */,
-          false /* origin_opt_out */, true /* save_data_enabled */,
-          {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */, hint_version_string);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->NavigateToUntrackedUrl();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              123 /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
-}
-
-TEST_F(PreviewsUKMObserverTest,
-       LogOptimizationGuideHintVersion_NoHintGenerationTimestamp) {
-  optimization_guide::proto::Version hint_version;
-  hint_version.set_hint_source(
-      optimization_guide::proto::HINT_SOURCE_OPTIMIZATION_HINTS_COMPONENT);
-  std::string hint_version_string;
-  hint_version.SerializeToString(&hint_version_string);
-  base::Base64Encode(hint_version_string, &hint_version_string);
-  RunTest(content::PREVIEWS_OFF /* committed_state */,
-          content::PREVIEWS_UNSPECIFIED /* allowed_state */,
-          false /* origin_opt_out */, true /* save_data_enabled */,
-          {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */, hint_version_string);
-
-  tester()->NavigateToUntrackedUrl();
-
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              1 /* hint_source */);
-}
-
-TEST_F(PreviewsUKMObserverTest,
-       LogOptimizationGuideHintVersion_NotActuallyAVersionProto) {
-  RunTest(content::PREVIEWS_OFF /* committed_state */,
-          content::PREVIEWS_UNSPECIFIED /* allowed_state */,
-          false /* origin_opt_out */, true /* save_data_enabled */,
-          {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */, "notahintversion");
-
-  tester()->NavigateToUntrackedUrl();
-
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(
+      content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+      false /* origin_opt_out_expected */,
+      true /* save_data_enabled_expected */, false /* previews_likely */,
+      {{PreviewsType::OFFLINE,
+        PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
+       {PreviewsType::LITE_PAGE,
+        PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE},
+       {PreviewsType::NOSCRIPT,
+        PreviewsEligibilityReason::BLACKLIST_DATA_NOT_LOADED},
+       {PreviewsType::LITE_PAGE_REDIRECT,
+        PreviewsEligibilityReason::
+            BLACKLIST_DATA_NOT_LOADED}} /* eligibility_reasons */,
+      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, CheckReportingForHidden) {
@@ -916,18 +703,15 @@ TEST_F(PreviewsUKMObserverTest, CheckReportingForHidden) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, true /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   web_contents()->WasHidden();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, CheckReportingForFlushMetrics) {
@@ -935,18 +719,15 @@ TEST_F(PreviewsUKMObserverTest, CheckReportingForFlushMetrics) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, true /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
 
   tester()->SimulateAppEnterBackground();
 
-  ValidateUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
-              false /* origin_opt_out_expected */,
-              true /* save_data_enabled_expected */,
-              false /* previews_likely */, {} /* eligibility_reasons */,
-              base::nullopt /* navigation_restart_penalty */,
-              base::nullopt /* hint_generation_timestamp */,
-              base::nullopt /* hint_source */);
+  ValidatePreviewsUKM(content::PREVIEWS_UNSPECIFIED, 0 /* opt_out_value */,
+                      false /* origin_opt_out_expected */,
+                      true /* save_data_enabled_expected */,
+                      false /* previews_likely */, {} /* eligibility_reasons */,
+                      base::nullopt /* navigation_restart_penalty */);
 }
 
 TEST_F(PreviewsUKMObserverTest, TestPageEndReasonUMA) {
@@ -957,8 +738,7 @@ TEST_F(PreviewsUKMObserverTest, TestPageEndReasonUMA) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
   tester()->NavigateToUntrackedUrl();
   histogram_tester.ExpectUniqueSample(
       "Previews.PageEndReason.None",
@@ -971,8 +751,7 @@ TEST_F(PreviewsUKMObserverTest, TestPageEndReasonUMA) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
   tester()->NavigateToUntrackedUrl();
   histogram_tester.ExpectUniqueSample(
       "Previews.PageEndReason.LitePageRedirect",
@@ -986,8 +765,7 @@ TEST_F(PreviewsUKMObserverTest, TestPageEndReasonUMA) {
           content::PREVIEWS_UNSPECIFIED /* allowed_state */,
           false /* origin_opt_out */, false /* save_data_enabled */,
           {} /* eligibility_reasons */,
-          base::nullopt /* navigation_restart_penalty */,
-          base::nullopt /* hint_version_string */);
+          base::nullopt /* navigation_restart_penalty */);
   tester()->NavigateToUntrackedUrl();
   histogram_tester.ExpectUniqueSample(
       "Previews.PageEndReason.DeferAllScript",

components/previews/content/previews_user_data.cc

@@ -33,8 +33,7 @@ PreviewsUserData::PreviewsUserData(const PreviewsUserData& other)
       committed_previews_state_without_holdback_(
           other.committed_previews_state_without_holdback_),
       coin_flip_holdback_result_(other.coin_flip_holdback_result_),
-      preview_eligibility_reasons_(other.preview_eligibility_reasons_),
-      serialized_hint_version_string_(other.serialized_hint_version_string_) {
+      preview_eligibility_reasons_(other.preview_eligibility_reasons_) {
   if (other.server_lite_page_info_) {
     server_lite_page_info_ =
         std::make_unique<ServerLitePageInfo>(*other.server_lite_page_info_);

components/previews/content/previews_user_data.h

@@ -181,15 +181,6 @@ class PreviewsUserData {
     server_lite_page_info_ = std::move(info);
   }
 
-  // The serialized hints version for the hint that was used for the page load.
-  base::Optional<std::string> serialized_hint_version_string() const {
-    return serialized_hint_version_string_;
-  }
-  void set_serialized_hint_version_string(
-      const std::string& serialized_hint_version_string) {
-    serialized_hint_version_string_ = serialized_hint_version_string;
-  }
-
  private:
   // A session unique ID related to this navigation.
   const uint64_t page_id_;
@@ -247,9 +238,6 @@ class PreviewsUserData {
   std::unordered_map<PreviewsType, PreviewsEligibilityReason>
       preview_eligibility_reasons_ = {};
 
-  // The serialized hints version for the hint that was used for the page load.
-  base::Optional<std::string> serialized_hint_version_string_ = base::nullopt;
-
   DISALLOW_ASSIGN(PreviewsUserData);
 };
 

components/previews/content/previews_user_data_unittest.cc

@@ -46,7 +46,6 @@ TEST(PreviewsUserDataTest, DeepCopy) {
   EXPECT_FALSE(data->black_listed_for_lite_page());
   EXPECT_FALSE(data->offline_preview_used());
   EXPECT_EQ(data->server_lite_page_info(), nullptr);
-  EXPECT_EQ(base::nullopt, data->serialized_hint_version_string());
 
   base::TimeTicks now = base::TimeTicks::Now();
 
@@ -58,7 +57,6 @@ TEST(PreviewsUserDataTest, DeepCopy) {
   data->set_server_lite_page_info(
       std::make_unique<PreviewsUserData::ServerLitePageInfo>());
   data->server_lite_page_info()->original_navigation_start = now;
-  data->set_serialized_hint_version_string("someversion");
 
   PreviewsUserData data_copy(*data);
   EXPECT_EQ(id, data_copy.page_id());
@@ -71,7 +69,6 @@ TEST(PreviewsUserDataTest, DeepCopy) {
   EXPECT_TRUE(data_copy.offline_preview_used());
   EXPECT_NE(data->server_lite_page_info(), nullptr);
   EXPECT_EQ(data->server_lite_page_info()->original_navigation_start, now);
-  EXPECT_EQ("someversion", data->serialized_hint_version_string());
 }
 
 TEST(PreviewsUserDataTest, TestCoinFlip_HasCommittedPreviewsType) {