Remove rarely useful tab activity metrics

Remove the following tab metrics because they're too uniform to be
useful in predictive models:

* ContentType: Almost always CONTENT_TYPE_TEXT_HTML (corresponding to
  normal web pages, as opposed to e.g. application/pdf).
* IsExtensionProtected: Almost never true.
* DefaultProtocolHandler: Rarely populated.

Bug: 784639
Change-Id: Ie40b268ab873d71305a59ae9b6356a8e105ceb31
Reviewed-on: https://chromium-review.googlesource.com/1036858Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Commit-Queue: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556000}

chrome/browser/chromeos/power/ml/user_activity_manager.h

@@ -45,6 +45,7 @@ struct TabProperty {
   // Tab URL's engagement score. -1 if engagement service is disabled.
   int engagement_score;
   // Tab content type.
+  // TODO(michaelpg): Move definition into user_activity_event.proto.
   metrics::TabMetricsEvent::ContentType content_type;
   // Whether user has form entry, i.e. text input.
   bool has_form_entry;

chrome/browser/chromeos/power/ml/user_activity_ukm_logger_impl.h

@@ -7,7 +7,6 @@
 
 #include "base/macros.h"
 #include "chrome/browser/chromeos/power/ml/user_activity_ukm_logger.h"
-#include "chrome/browser/resource_coordinator/tab_metrics_event.pb.h"
 #include "services/metrics/public/cpp/ukm_recorder.h"
 
 namespace chromeos {

chrome/browser/resource_coordinator/tab_activity_watcher_browsertest.cc

@@ -5,7 +5,6 @@
 #include <memory>
 
 #include "base/macros.h"
-#include "chrome/browser/resource_coordinator/tab_metrics_event.pb.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
@@ -19,7 +18,6 @@
 #include "services/metrics/public/mojom/ukm_interface.mojom.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using metrics::TabMetricsEvent;
 using ukm::builders::TabManager_TabMetrics;
 using ukm::builders::TabManager_Background_ForegroundedOrClosed;
 
@@ -33,12 +31,8 @@ const char* kFOCEntryName =
 
 // The default metric values for a tab.
 const UkmMetricMap kBasicMetricValues({
-    {TabManager_TabMetrics::kContentTypeName,
-     TabMetricsEvent::CONTENT_TYPE_TEXT_HTML},
-    {TabManager_TabMetrics::kDefaultProtocolHandlerName, base::nullopt},
     {TabManager_TabMetrics::kHasBeforeUnloadHandlerName, 0},
     {TabManager_TabMetrics::kHasFormEntryName, 0},
-    {TabManager_TabMetrics::kIsExtensionProtectedName, 0},
     {TabManager_TabMetrics::kIsPinnedName, 0},
     {TabManager_TabMetrics::kKeyEventCountName, 0},
     {TabManager_TabMetrics::kNavigationEntryCountName, 1},

chrome/browser/resource_coordinator/tab_activity_watcher_unittest.cc

@@ -8,11 +8,8 @@
 
 #include "base/macros.h"
 #include "base/test/simple_test_tick_clock.h"
-#include "chrome/browser/browser_process.h"
 #include "chrome/browser/engagement/site_engagement_service.h"
 #include "chrome/browser/resource_coordinator/tab_activity_watcher.h"
-#include "chrome/browser/resource_coordinator/tab_manager.h"
-#include "chrome/browser/resource_coordinator/tab_metrics_event.pb.h"
 #include "chrome/browser/resource_coordinator/time.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_activity_simulator.h"
@@ -34,7 +31,6 @@
 
 using blink::WebInputEvent;
 using content::WebContentsTester;
-using metrics::TabMetricsEvent;
 using ukm::builders::TabManager_TabMetrics;
 using ForegroundedOrClosed =
     ukm::builders::TabManager_Background_ForegroundedOrClosed;
@@ -50,18 +46,14 @@ const GURL kTestUrls[] = {
 
 // The default metric values for a tab.
 const UkmMetricMap kBasicMetricValues({
-    {TabManager_TabMetrics::kContentTypeName,
-     TabMetricsEvent::CONTENT_TYPE_TEXT_HTML},
     {TabManager_TabMetrics::kHasBeforeUnloadHandlerName, 0},
     {TabManager_TabMetrics::kHasFormEntryName, 0},
-    {TabManager_TabMetrics::kIsExtensionProtectedName, 0},
     {TabManager_TabMetrics::kIsPinnedName, 0},
     {TabManager_TabMetrics::kKeyEventCountName, 0},
     {TabManager_TabMetrics::kMouseEventCountName, 0},
     {TabManager_TabMetrics::kSiteEngagementScoreName, 0},
     {TabManager_TabMetrics::kTouchEventCountName, 0},
     {TabManager_TabMetrics::kWasRecentlyAudibleName, 0},
-    {TabManager_TabMetrics::kDefaultProtocolHandlerName, base::nullopt},
 });
 
 blink::WebMouseEvent CreateMouseEvent(WebInputEvent::Type event_type) {
@@ -248,11 +240,6 @@ TEST_F(TabMetricsTest, TabMetrics) {
     ExpectNewEntry(kTestUrls[1], expected_metrics);
   }
 
-  // Simulate an extension protecting the tab.
-  g_browser_process->GetTabManager()->SetTabAutoDiscardableState(
-      test_contents_2, false);
-  expected_metrics[TabManager_TabMetrics::kIsExtensionProtectedName] = 1;
-
   // Site engagement score should round down to the nearest 10.
   SiteEngagementService::Get(profile())->ResetBaseScoreForURL(kTestUrls[1], 45);
   expected_metrics[TabManager_TabMetrics::kSiteEngagementScoreName] = 40;

chrome/browser/resource_coordinator/tab_features.h

@@ -9,7 +9,6 @@
 #include <string>
 
 #include "base/optional.h"
-#include "chrome/browser/resource_coordinator/tab_metrics_event.pb.h"
 #include "ui/base/page_transition_types.h"
 
 namespace resource_coordinator {
@@ -25,11 +24,8 @@ struct TabFeatures {
   // Keep properties in alphabetical order to match the order in
   // TabMetricsLogger::LogBackgroundTab() and make it easier to check which
   // properties are sent via UKM.
-  metrics::TabMetricsEvent::ContentType content_type =
-      metrics::TabMetricsEvent::CONTENT_TYPE_UNKNOWN;
   bool has_before_unload_handler = false;
   bool has_form_entry = false;
-  bool is_extension_protected = false;
   bool is_pinned = false;
   int32_t key_event_count = 0;
   int32_t mouse_event_count = 0;

chrome/browser/resource_coordinator/tab_metrics_event.proto

@@ -44,40 +44,6 @@ message TabMetricsEvent {
   }
 
   optional ContentType content_type = 1;
-
-  // URI schemes that can be handled by a protocol handler.
-  enum ProtocolHandlerScheme {
-    option allow_alias = true;  // Allow LAST alias for static assertions.
-
-    // Not one of the below, including custom handlers.
-    PROTOCOL_HANDLER_SCHEME_OTHER = 0;
-
-    // Schemes whitelisted for registerProtocolHandler.
-    PROTOCOL_HANDLER_SCHEME_BITCOIN = 1;
-    PROTOCOL_HANDLER_SCHEME_GEO = 2;
-    PROTOCOL_HANDLER_SCHEME_IM = 3;
-    PROTOCOL_HANDLER_SCHEME_IRC = 4;
-    PROTOCOL_HANDLER_SCHEME_IRCS = 5;
-    PROTOCOL_HANDLER_SCHEME_MAGNET = 6;
-    PROTOCOL_HANDLER_SCHEME_MAILTO = 7;
-    PROTOCOL_HANDLER_SCHEME_MMS = 8;
-    PROTOCOL_HANDLER_SCHEME_NEWS = 9;
-    PROTOCOL_HANDLER_SCHEME_NNTP = 10;
-    PROTOCOL_HANDLER_SCHEME_OPENPGP4FPR = 11;
-    PROTOCOL_HANDLER_SCHEME_SIP = 12;
-    PROTOCOL_HANDLER_SCHEME_SMS = 13;
-    PROTOCOL_HANDLER_SCHEME_SMSTO = 14;
-    PROTOCOL_HANDLER_SCHEME_SSH = 15;
-    PROTOCOL_HANDLER_SCHEME_TEL = 16;
-    PROTOCOL_HANDLER_SCHEME_URN = 17;
-    PROTOCOL_HANDLER_SCHEME_WEBCAL = 18;
-    PROTOCOL_HANDLER_SCHEME_WTAI = 19;
-    PROTOCOL_HANDLER_SCHEME_XMPP = 20;
-
-    PROTOCOL_HANDLER_SCHEME_LAST = 20;
-  }
-
-  repeated ProtocolHandlerScheme enabled_protocol_handlers = 2;
 }
 
 // Defines specialized fields used by the TabManager.WindowMetrics UKM event

chrome/browser/resource_coordinator/tab_metrics_logger.cc

@@ -6,22 +6,17 @@
 
 #include <algorithm>
 #include <string>
-#include <vector>
 
 #include "base/stl_util.h"
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/custom_handlers/protocol_handler_registry.h"
-#include "chrome/browser/custom_handlers/protocol_handler_registry_factory.h"
 #include "chrome/browser/engagement/site_engagement_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/resource_coordinator/tab_features.h"
-#include "chrome/browser/resource_coordinator/tab_lifecycle_unit_external.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
-#include "chrome/common/custom_handlers/protocol_handler.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/page_importance_signals.h"
@@ -34,61 +29,6 @@ using metrics::TabMetricsEvent;
 
 namespace {
 
-// Order must match the metrics.TabMetricsEvent.Scheme enum.
-const char* kWhitelistedSchemes[] = {
-    "",  // Placeholder for PROTOCOL_HANDLER_SCHEME_OTHER.
-    "bitcoin", "geo",  "im",   "irc",         "ircs", "magnet", "mailto",
-    "mms",     "news", "nntp", "openpgp4fpr", "sip",  "sms",    "smsto",
-    "ssh",     "tel",  "urn",  "webcal",      "wtai", "xmpp",
-};
-
-// Adds a DefaultProtocolHandler metric with the handler's scheme to |entry|
-// if the protocol handler is a default protocol handler.
-void PopulateSchemeForHandler(ProtocolHandlerRegistry* registry,
-                              const ProtocolHandler& handler,
-                              ukm::builders::TabManager_TabMetrics* entry) {
-  if (registry->IsDefault(handler)) {
-    // Append a DefaultProtocolHandler metric whose value is the scheme.
-    // Note that multiple DefaultProtocolHandler metrics may be added, one for
-    // each scheme the entry's origin handles by default.
-    entry->SetDefaultProtocolHandler(
-        TabMetricsLogger::GetSchemeValueFromString(handler.protocol()));
-  }
-}
-
-// Populates the protocol handler fields based on the WebContents' origin.
-// We match the origin instead of the full page URL because:
-// - a handler relevant for one page is probably relevant for the whole site
-// - a handler maps to a template string, so matching on a full URL is hard
-// - even if this page was opened from a protocol handler, a redirect may have
-//   changed the URL anyway.
-void PopulateProtocolHandlers(content::WebContents* web_contents,
-                              ukm::builders::TabManager_TabMetrics* entry) {
-  ProtocolHandlerRegistry* registry =
-      ProtocolHandlerRegistryFactory::GetForBrowserContext(
-          web_contents->GetBrowserContext());
-  // May be null in tests.
-  if (!registry)
-    return;
-
-  const GURL origin = web_contents->GetLastCommittedURL().GetOrigin();
-  if (origin.is_empty())
-    return;
-
-  // Fetch all schemes that have been registered (accepted or denied).
-  std::vector<std::string> registered_schemes;
-  registry->GetRegisteredProtocols(&registered_schemes);
-
-  // Protocol handlers are stored by scheme, not URL. For each scheme, find the
-  // URLs of the handlers registered for it.
-  for (const std::string& scheme : registered_schemes) {
-    for (const ProtocolHandler& handler : registry->GetHandlersFor(scheme)) {
-      if (handler.url().GetOrigin() == origin)
-        PopulateSchemeForHandler(registry, handler, entry);
-    }
-  }
-}
-
 // Populates navigation-related metrics.
 void PopulatePageTransitionFeatures(resource_coordinator::TabFeatures* tab,
                                     ui::PageTransition page_transition) {
@@ -154,18 +94,6 @@ TabMetricsEvent::ContentType TabMetricsLogger::GetContentTypeFromMimeType(
   return TabMetricsEvent::CONTENT_TYPE_OTHER;
 }
 
-// static
-TabMetricsEvent::ProtocolHandlerScheme
-TabMetricsLogger::GetSchemeValueFromString(const std::string& scheme) {
-  const char* const* const scheme_ptr = std::find(
-      std::begin(kWhitelistedSchemes), std::end(kWhitelistedSchemes), scheme);
-  if (scheme_ptr == std::end(kWhitelistedSchemes))
-    return TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OTHER;
-
-  size_t index = scheme_ptr - std::begin(kWhitelistedSchemes);
-  return static_cast<TabMetricsEvent::ProtocolHandlerScheme>(index);
-}
-
 // static
 int TabMetricsLogger::GetSiteEngagementScore(
     const content::WebContents* web_contents) {
@@ -195,18 +123,11 @@ resource_coordinator::TabFeatures TabMetricsLogger::GetTabFeatures(
 
   resource_coordinator::TabFeatures tab;
 
-  TabMetricsEvent::ContentType content_type =
-      GetContentTypeFromMimeType(web_contents->GetContentsMimeType());
-  tab.content_type = content_type;
   tab.has_before_unload_handler =
       web_contents->GetMainFrame()->GetSuddenTerminationDisablerState(
           blink::kBeforeUnloadHandler);
   tab.has_form_entry =
       web_contents->GetPageImportanceSignals().had_form_interaction;
-  tab.is_extension_protected =
-      !resource_coordinator::TabLifecycleUnitExternal::FromWebContents(
-           web_contents)
-           ->IsAutoDiscardable();
 
   int index = tab_strip_model->GetIndexOfWebContents(web_contents);
   DCHECK_NE(index, TabStripModel::kNoTab);
@@ -259,16 +180,12 @@ void TabMetricsLogger::LogBackgroundTab(ukm::SourceId ukm_source_id,
   ukm::builders::TabManager_TabMetrics entry(ukm_source_id);
   resource_coordinator::TabFeatures tab = GetTabFeatures(browser, tab_metrics);
 
-  PopulateProtocolHandlers(web_contents, &entry);
-
   // Keep these Set functions in alphabetical order so they're easy to check
   // against the list of metrics in the UKM event.
   // TODO(michaelpg): Add PluginType field if mime type matches "application/*"
   // using PluginUMAReporter.
-  entry.SetContentType(tab.content_type);
   entry.SetHasBeforeUnloadHandler(tab.has_before_unload_handler);
   entry.SetHasFormEntry(tab.has_form_entry);
-  entry.SetIsExtensionProtected(tab.is_extension_protected);
   entry.SetIsPinned(tab.is_pinned);
   entry.SetKeyEventCount(tab.key_event_count);
   entry.SetMouseEventCount(tab.mouse_event_count);

chrome/browser/resource_coordinator/tab_metrics_logger.h

@@ -86,12 +86,6 @@ class TabMetricsLogger {
   static metrics::TabMetricsEvent::ContentType GetContentTypeFromMimeType(
       const std::string& mime_type);
 
-  // Returns the ProtocolHandlerScheme enumerator matching the string.
-  // The enumerator value is used in the UKM entry, since UKM entries can't
-  // store strings.
-  static metrics::TabMetricsEvent::ProtocolHandlerScheme
-  GetSchemeValueFromString(const std::string& scheme);
-
   // Returns the site engagement score for the WebContents, rounded down to 10s
   // to limit granularity. Returns -1 if site engagement service is disabled.
   static int GetSiteEngagementScore(const content::WebContents* web_contents);

chrome/browser/resource_coordinator/tab_metrics_logger_unittest.cc

@@ -7,8 +7,6 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/engagement/site_engagement_service.h"
 #include "chrome/browser/resource_coordinator/tab_features.h"
-#include "chrome/browser/resource_coordinator/tab_manager.h"
-#include "chrome/browser/resource_coordinator/tab_metrics_event.pb.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_activity_simulator.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
@@ -19,7 +17,6 @@
 #include "content/public/test/web_contents_tester.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using metrics::TabMetricsEvent;
 using content::WebContentsTester;
 
 // Sanity checks for functions in TabMetricsLogger.
@@ -53,11 +50,8 @@ TEST_F(TabMetricsLoggerTest, TabFeatures) {
 
     resource_coordinator::TabFeatures bg_features =
         TabMetricsLogger::GetTabFeatures(browser.get(), bg_metrics);
-    EXPECT_EQ(TabMetricsEvent::CONTENT_TYPE_TEXT_HTML,
-              bg_features.content_type);
     EXPECT_EQ(bg_features.has_before_unload_handler, false);
     EXPECT_EQ(bg_features.has_form_entry, false);
-    EXPECT_EQ(bg_features.is_extension_protected, false);
     EXPECT_EQ(bg_features.is_pinned, false);
     EXPECT_EQ(bg_features.key_event_count, 0);
     EXPECT_EQ(bg_features.mouse_event_count, 0);
@@ -80,9 +74,6 @@ TEST_F(TabMetricsLoggerTest, TabFeatures) {
   tab_activity_simulator.Navigate(bg_contents, GURL("https://www.chromium.org"),
                                   page_transition);
   tab_strip_model->SetTabPinned(1, true);
-  // Simulate an extension protecting a tab.
-  g_browser_process->GetTabManager()->SetTabAutoDiscardableState(bg_contents,
-                                                                 false);
   SiteEngagementService::Get(profile())->ResetBaseScoreForURL(
       GURL("https://www.chromium.org"), 91);
 
@@ -96,11 +87,8 @@ TEST_F(TabMetricsLoggerTest, TabFeatures) {
 
     resource_coordinator::TabFeatures bg_features =
         TabMetricsLogger::GetTabFeatures(browser.get(), bg_metrics);
-    EXPECT_EQ(TabMetricsEvent::CONTENT_TYPE_TEXT_HTML,
-              bg_features.content_type);
     EXPECT_EQ(bg_features.has_before_unload_handler, false);
     EXPECT_EQ(bg_features.has_form_entry, false);
-    EXPECT_EQ(bg_features.is_extension_protected, true);
     EXPECT_EQ(bg_features.is_pinned, true);
     EXPECT_EQ(bg_features.key_event_count, 3);
     EXPECT_EQ(bg_features.mouse_event_count, 42);
@@ -120,74 +108,3 @@ TEST_F(TabMetricsLoggerTest, TabFeatures) {
 
   tab_strip_model->CloseAllTabs();
 }
-
-// Tests that protocol schemes are mapped to the correct enumerators.
-TEST_F(TabMetricsLoggerTest, Schemes) {
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_BITCOIN,
-            TabMetricsLogger::GetSchemeValueFromString("bitcoin"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_GEO,
-            TabMetricsLogger::GetSchemeValueFromString("geo"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_IM,
-            TabMetricsLogger::GetSchemeValueFromString("im"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_IRC,
-            TabMetricsLogger::GetSchemeValueFromString("irc"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_IRCS,
-            TabMetricsLogger::GetSchemeValueFromString("ircs"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_MAGNET,
-            TabMetricsLogger::GetSchemeValueFromString("magnet"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_MAILTO,
-            TabMetricsLogger::GetSchemeValueFromString("mailto"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_MMS,
-            TabMetricsLogger::GetSchemeValueFromString("mms"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_NEWS,
-            TabMetricsLogger::GetSchemeValueFromString("news"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_NNTP,
-            TabMetricsLogger::GetSchemeValueFromString("nntp"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OPENPGP4FPR,
-            TabMetricsLogger::GetSchemeValueFromString("openpgp4fpr"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_SIP,
-            TabMetricsLogger::GetSchemeValueFromString("sip"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_SMS,
-            TabMetricsLogger::GetSchemeValueFromString("sms"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_SMSTO,
-            TabMetricsLogger::GetSchemeValueFromString("smsto"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_SSH,
-            TabMetricsLogger::GetSchemeValueFromString("ssh"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_TEL,
-            TabMetricsLogger::GetSchemeValueFromString("tel"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_URN,
-            TabMetricsLogger::GetSchemeValueFromString("urn"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_WEBCAL,
-            TabMetricsLogger::GetSchemeValueFromString("webcal"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_WTAI,
-            TabMetricsLogger::GetSchemeValueFromString("wtai"));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_XMPP,
-            TabMetricsLogger::GetSchemeValueFromString("xmpp"));
-
-  static_assert(
-      TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_LAST ==
-              TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_XMPP &&
-          TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_LAST == 20,
-      "This test and the scheme list in TabMetricsLoggerImpl must be updated "
-      "when new protocol handlers are added.");
-}
-
-// Tests non-whitelisted protocol schemes.
-TEST_F(TabMetricsLoggerTest, NonWhitelistedSchemes) {
-  // Native (non-web-based) handler.
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OTHER,
-            TabMetricsLogger::GetSchemeValueFromString("foo"));
-
-  // Custom ("web+") protocol handlers.
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OTHER,
-            TabMetricsLogger::GetSchemeValueFromString("web+foo"));
-  // "mailto" after the web+ prefix doesn't trigger any special handling.
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OTHER,
-            TabMetricsLogger::GetSchemeValueFromString("web+mailto"));
-
-  // Nonsense protocol handlers.
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OTHER,
-            TabMetricsLogger::GetSchemeValueFromString(""));
-  EXPECT_EQ(TabMetricsEvent::PROTOCOL_HANDLER_SCHEME_OTHER,
-            TabMetricsLogger::GetSchemeValueFromString("mailto-xyz"));
-}

tools/metrics/ukm/ukm.xml

@@ -3524,16 +3524,17 @@ be describing additional metrics about the same event.
   </summary>
   <metric name="ContentType">
     <summary>
-      Enumeration for the MIME type of the page. Values are enumerated in
-      metrics::TabMetricsEvent::ContentType.
+      Obsolete. Enumeration for the MIME type of the page. Values are enumerated
+      in metrics::TabMetricsEvent::ContentType.
     </summary>
   </metric>
   <metric name="DefaultProtocolHandler">
     <summary>
-      Schemes that a page from this page's origin is the default protocol
-      handler for, meaning the user has chosen to accept (or the handler was
-      preinstalled by Chrome). The metric is repeated, occurring for each such
-      protocol handler, and uses values from metrics::TabMetricsEvent::Scheme.
+      Obsolete. Schemes that a page from this page's origin is the default
+      protocol handler for, meaning the user has chosen to accept (or the
+      handler was preinstalled by Chrome). The metric is repeated, occurring for
+      each such protocol handler, and uses values from
+      metrics::TabMetricsEvent::Scheme.
     </summary>
   </metric>
   <metric name="HasBeforeUnloadHandler">
@@ -3549,8 +3550,8 @@ be describing additional metrics about the same event.
   </metric>
   <metric name="IsExtensionProtected">
     <summary>
-      True if an extension has marked this tab as non-discardable via the
-      chrome.tabs.update() extension API.
+      Obsolete. True if an extension has marked this tab as non-discardable via
+      the chrome.tabs.update() extension API.
     </summary>
   </metric>
   <metric name="IsPinned">