Logs a previews coin flip holdback event to interventions-internals page

Currently there is no visibility in interventions-internals if a coin
flip is preventing you from seeing a preview. This posts a new event
to that page when a coin flip happens.

Bug: 1000436
Change-Id: I5e1367891acb3e5f57e045a6e55335b081a25357
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1785821
Commit-Queue: Doug Arnett <dougarnett@chromium.org>
Reviewed-by: Robert Ogden <robertogden@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693836}

chrome/browser/previews/previews_content_util.cc

@@ -14,6 +14,7 @@
 #include "base/optional.h"
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
+#include "base/time/default_clock.h"
 #include "chrome/browser/content_settings/cookie_settings_factory.h"
 #include "chrome/browser/data_reduction_proxy/data_reduction_proxy_chrome_settings.h"
 #include "chrome/browser/data_reduction_proxy/data_reduction_proxy_chrome_settings_factory.h"
@@ -29,6 +30,7 @@
 #include "components/content_settings/core/browser/cookie_settings.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_data.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_request_options.h"
+#include "components/previews/content/previews_ui_service.h"
 #include "components/previews/content/previews_user_data.h"
 #include "components/previews/core/previews_experiments.h"
 #include "components/previews/core/previews_features.h"
@@ -357,6 +359,26 @@ void UpdatePreviewsUserDataAndRecordCoinFlipResult(
     previews::CoinFlipHoldbackResult result) {
   DCHECK_NE(result, previews::CoinFlipHoldbackResult::kNotSet);
 
+  // Log a coin flip holdback to the interventions-internals page.
+  if (result == previews::CoinFlipHoldbackResult::kHoldback) {
+    auto* previews_service =
+        navigation_handle && navigation_handle->GetWebContents()
+            ? PreviewsServiceFactory::GetForProfile(Profile::FromBrowserContext(
+                  navigation_handle->GetWebContents()->GetBrowserContext()))
+            : nullptr;
+    if (previews_service && previews_service->previews_ui_service()) {
+      PreviewsEligibilityReason reason =
+          PreviewsEligibilityReason::COINFLIP_HOLDBACK;
+      PreviewsType type =
+          previews_user_data->PreHoldbackCommittedPreviewsType();
+      std::vector<PreviewsEligibilityReason> passed_reasons;
+      previews_service->previews_ui_service()->LogPreviewDecisionMade(
+          reason, navigation_handle->GetURL(),
+          base::DefaultClock::GetInstance()->Now(), type,
+          std::move(passed_reasons), previews_user_data->page_id());
+    }
+  }
+
   // We only want to record the coin flip once per navigation when set, so if it
   // is already set then we're done.
   if (previews_user_data->coin_flip_holdback_result() !=

components/previews/core/previews_black_list.h

@@ -85,6 +85,8 @@ enum class PreviewsEligibilityReason {
   // optimization guide did not allow this preview type in the current browser
   // conditions.
   NOT_ALLOWED_BY_OPTIMIZATION_GUIDE = 19,
+  // The preview was not performed due to a coinflip experiment holdback.
+  COINFLIP_HOLDBACK = 20,
   LAST,
 };
 

components/previews/core/previews_logger.cc

@@ -98,6 +98,9 @@ std::string GetReasonDescription(PreviewsEligibilityReason reason,
     case PreviewsEligibilityReason::NOT_ALLOWED_BY_OPTIMIZATION_GUIDE:
       return want_inverse_description ? "Allowed by server rules"
                                       : "Not allowed by server rules";
+    case PreviewsEligibilityReason::COINFLIP_HOLDBACK:
+      DCHECK(!want_inverse_description);
+      return "Coin flip holdback encountered";
     case PreviewsEligibilityReason::LAST:
       break;
   }

tools/metrics/histograms/enums.xml

@@ -49250,6 +49250,7 @@ Called by update_net_trust_anchors.py.-->
   <int value="17" label="Optimization hints not loaded."/>
   <int value="18" label="The navigation URL had an excluded media suffix."/>
   <int value="19" label="Not allowed by server rules provided to the client."/>
+  <int value="20" label="Coin flip holdback encountered."/>
 </enum>
 
 <enum name="PreviewsHintCacheLevelDBStoreLoadMetadataResult">