Add more aggressively targeted variants of MultiTabLoading metrics

This adds variants of PageLoad.Clients.MultiTabLoading.* metrics that
are recorded only when there are >=2 (or >=5) inflight loading tabs.

Bug: 792759
Change-Id: Ic1c8711d6424752dd80685b7740ec12fcc1c885e
Reviewed-on: https://chromium-review.googlesource.com/826706Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524329}

chrome/browser/BUILD.gn

@@ -904,6 +904,8 @@ split_static_library("browser") {
     "page_load_metrics/observers/from_gws_page_load_metrics_observer.h",
     "page_load_metrics/observers/google_captcha_observer.cc",
     "page_load_metrics/observers/google_captcha_observer.h",
+    "page_load_metrics/observers/histogram_suffixes.cc",
+    "page_load_metrics/observers/histogram_suffixes.h",
     "page_load_metrics/observers/https_engagement_metrics/https_engagement_page_load_metrics_observer.cc",
     "page_load_metrics/observers/https_engagement_metrics/https_engagement_page_load_metrics_observer.h",
     "page_load_metrics/observers/https_engagement_metrics/https_engagement_service.cc",

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc

@@ -13,6 +13,7 @@
 #include "chrome/browser/loader/chrome_navigation_data.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings_factory.h"
+#include "chrome/browser/page_load_metrics/observers/histogram_suffixes.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "chrome/browser/previews/previews_infobar_delegate.h"
@@ -72,25 +73,6 @@ const char kHistogramDataReductionProxyPrefix[] =
     "PageLoad.Clients.DataReductionProxy.";
 const char kHistogramDataReductionProxyLoFiOnPrefix[] =
     "PageLoad.Clients.DataReductionProxy.LoFiOn.";
-const char kHistogramDOMContentLoadedEventFiredSuffix[] =
-    "DocumentTiming.NavigationToDOMContentLoadedEventFired";
-const char kHistogramFirstLayoutSuffix[] =
-    "DocumentTiming.NavigationToFirstLayout";
-const char kHistogramLoadEventFiredSuffix[] =
-    "DocumentTiming.NavigationToLoadEventFired";
-const char kHistogramFirstContentfulPaintSuffix[] =
-    "PaintTiming.NavigationToFirstContentfulPaint";
-const char kHistogramFirstMeaningfulPaintSuffix[] =
-    "Experimental.PaintTiming.NavigationToFirstMeaningfulPaint";
-const char kHistogramFirstImagePaintSuffix[] =
-    "PaintTiming.NavigationToFirstImagePaint";
-const char kHistogramFirstPaintSuffix[] = "PaintTiming.NavigationToFirstPaint";
-const char kHistogramFirstTextPaintSuffix[] =
-    "PaintTiming.NavigationToFirstTextPaint";
-const char kHistogramParseStartSuffix[] = "ParseTiming.NavigationToParseStart";
-const char kHistogramParseBlockedOnScriptLoadSuffix[] =
-    "ParseTiming.ParseBlockedOnScriptLoad";
-const char kHistogramParseDurationSuffix[] = "ParseTiming.ParseDuration";
 
 const char kResourcesPercentProxied[] =
     "Experimental.CompletedResources.Network.PercentProxied";
@@ -340,7 +322,7 @@ void DataReductionProxyMetricsObserver::OnDomContentLoadedEventStart(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.document_timing->dom_content_loaded_event_start,
-      internal::kHistogramDOMContentLoadedEventFiredSuffix);
+      ::internal::kHistogramDOMContentLoadedEventFiredSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnLoadEventStart(
@@ -349,7 +331,7 @@ void DataReductionProxyMetricsObserver::OnLoadEventStart(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.document_timing->load_event_start,
-      internal::kHistogramLoadEventFiredSuffix);
+      ::internal::kHistogramLoadEventFiredSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnFirstLayout(
@@ -358,16 +340,16 @@ void DataReductionProxyMetricsObserver::OnFirstLayout(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.document_timing->first_layout,
-      internal::kHistogramFirstLayoutSuffix);
+      ::internal::kHistogramFirstLayoutSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnFirstPaintInPage(
     const page_load_metrics::mojom::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(info, data_,
-                                          timing.paint_timing->first_paint,
-                                          internal::kHistogramFirstPaintSuffix);
+  RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
+      info, data_, timing.paint_timing->first_paint,
+      ::internal::kHistogramFirstPaintSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnFirstTextPaintInPage(
@@ -376,7 +358,7 @@ void DataReductionProxyMetricsObserver::OnFirstTextPaintInPage(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.paint_timing->first_text_paint,
-      internal::kHistogramFirstTextPaintSuffix);
+      ::internal::kHistogramFirstTextPaintSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnFirstImagePaintInPage(
@@ -385,7 +367,7 @@ void DataReductionProxyMetricsObserver::OnFirstImagePaintInPage(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.paint_timing->first_image_paint,
-      internal::kHistogramFirstImagePaintSuffix);
+      ::internal::kHistogramFirstImagePaintSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnFirstContentfulPaintInPage(
@@ -394,7 +376,7 @@ void DataReductionProxyMetricsObserver::OnFirstContentfulPaintInPage(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.paint_timing->first_contentful_paint,
-      internal::kHistogramFirstContentfulPaintSuffix);
+      ::internal::kHistogramFirstContentfulPaintSuffix);
 }
 
 void DataReductionProxyMetricsObserver::
@@ -404,16 +386,16 @@ void DataReductionProxyMetricsObserver::
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
       info, data_, timing.paint_timing->first_meaningful_paint,
-      internal::kHistogramFirstMeaningfulPaintSuffix);
+      ::internal::kHistogramFirstMeaningfulPaintSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnParseStart(
     const page_load_metrics::mojom::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(info, data_,
-                                          timing.parse_timing->parse_start,
-                                          internal::kHistogramParseStartSuffix);
+  RECORD_FOREGROUND_HISTOGRAMS_FOR_SUFFIX(
+      info, data_, timing.parse_timing->parse_start,
+      ::internal::kHistogramParseStartSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnParseStop(
@@ -427,10 +409,10 @@ void DataReductionProxyMetricsObserver::OnParseStop(
   base::TimeDelta parse_duration = timing.parse_timing->parse_stop.value() -
                                    timing.parse_timing->parse_start.value();
   RECORD_HISTOGRAMS_FOR_SUFFIX(data_, parse_duration,
-                               internal::kHistogramParseDurationSuffix);
+                               ::internal::kHistogramParseDurationSuffix);
   RECORD_HISTOGRAMS_FOR_SUFFIX(
       data_, timing.parse_timing->parse_blocked_on_script_load_duration.value(),
-      internal::kHistogramParseBlockedOnScriptLoadSuffix);
+      ::internal::kHistogramParseBlockedOnScriptLoadSuffix);
 }
 
 void DataReductionProxyMetricsObserver::OnLoadedResource(

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc

@@ -17,6 +17,7 @@
 #include "base/time/time.h"
 #include "chrome/browser/loader/chrome_navigation_data.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
+#include "chrome/browser/page_load_metrics/observers/histogram_suffixes.h"
 #include "chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/page_load_tracker.h"
@@ -222,28 +223,30 @@ class DataReductionProxyMetricsObserverTest
 
   void ValidateHistograms() {
     ValidateHistogramsForSuffix(
-        internal::kHistogramDOMContentLoadedEventFiredSuffix,
+        ::internal::kHistogramDOMContentLoadedEventFiredSuffix,
         timing_.document_timing->dom_content_loaded_event_start);
-    ValidateHistogramsForSuffix(internal::kHistogramFirstLayoutSuffix,
+    ValidateHistogramsForSuffix(::internal::kHistogramFirstLayoutSuffix,
                                 timing_.document_timing->first_layout);
-    ValidateHistogramsForSuffix(internal::kHistogramLoadEventFiredSuffix,
+    ValidateHistogramsForSuffix(::internal::kHistogramLoadEventFiredSuffix,
                                 timing_.document_timing->load_event_start);
-    ValidateHistogramsForSuffix(internal::kHistogramFirstContentfulPaintSuffix,
-                                timing_.paint_timing->first_contentful_paint);
-    ValidateHistogramsForSuffix(internal::kHistogramFirstMeaningfulPaintSuffix,
-                                timing_.paint_timing->first_meaningful_paint);
-    ValidateHistogramsForSuffix(internal::kHistogramFirstImagePaintSuffix,
+    ValidateHistogramsForSuffix(
+        ::internal::kHistogramFirstContentfulPaintSuffix,
+        timing_.paint_timing->first_contentful_paint);
+    ValidateHistogramsForSuffix(
+        ::internal::kHistogramFirstMeaningfulPaintSuffix,
+        timing_.paint_timing->first_meaningful_paint);
+    ValidateHistogramsForSuffix(::internal::kHistogramFirstImagePaintSuffix,
                                 timing_.paint_timing->first_image_paint);
-    ValidateHistogramsForSuffix(internal::kHistogramFirstPaintSuffix,
+    ValidateHistogramsForSuffix(::internal::kHistogramFirstPaintSuffix,
                                 timing_.paint_timing->first_paint);
-    ValidateHistogramsForSuffix(internal::kHistogramFirstTextPaintSuffix,
+    ValidateHistogramsForSuffix(::internal::kHistogramFirstTextPaintSuffix,
                                 timing_.paint_timing->first_text_paint);
-    ValidateHistogramsForSuffix(internal::kHistogramParseStartSuffix,
+    ValidateHistogramsForSuffix(::internal::kHistogramParseStartSuffix,
                                 timing_.parse_timing->parse_start);
     ValidateHistogramsForSuffix(
-        internal::kHistogramParseBlockedOnScriptLoadSuffix,
+        ::internal::kHistogramParseBlockedOnScriptLoadSuffix,
         timing_.parse_timing->parse_blocked_on_script_load_duration);
-    ValidateHistogramsForSuffix(internal::kHistogramParseDurationSuffix,
+    ValidateHistogramsForSuffix(::internal::kHistogramParseDurationSuffix,
                                 timing_.parse_timing->parse_stop.value() -
                                     timing_.parse_timing->parse_start.value());
   }

chrome/browser/page_load_metrics/observers/histogram_suffixes.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/page_load_metrics/observers/histogram_suffixes.h"
+
+namespace internal {
+
+const char kHistogramDOMContentLoadedEventFiredBackgroundSuffix[] =
+    "DocumentTiming.NavigationToDOMContentLoadedEventFired.Background";
+const char kHistogramDOMContentLoadedEventFiredSuffix[] =
+    "DocumentTiming.NavigationToDOMContentLoadedEventFired";
+const char kHistogramFirstContentfulPaintSuffix[] =
+    "PaintTiming.NavigationToFirstContentfulPaint";
+const char kHistogramFirstImagePaintSuffix[] =
+    "PaintTiming.NavigationToFirstImagePaint";
+const char kHistogramFirstLayoutSuffix[] =
+    "DocumentTiming.NavigationToFirstLayout";
+const char kHistogramFirstMeaningfulPaintSuffix[] =
+    "Experimental.PaintTiming.NavigationToFirstMeaningfulPaint";
+const char kHistogramFirstPaintSuffix[] = "PaintTiming.NavigationToFirstPaint";
+const char kHistogramFirstTextPaintSuffix[] =
+    "PaintTiming.NavigationToFirstTextPaint";
+const char kHistogramForegroundToFirstContentfulPaintSuffix[] =
+    "PaintTiming.ForegroundToFirstContentfulPaint";
+const char kHistogramForegroundToFirstMeaningfulPaintSuffix[] =
+    "Experimental.PaintTiming.ForegroundToFirstMeaningfulPaint";
+const char kHistogramLoadEventFiredBackgroundSuffix[] =
+    "DocumentTiming.NavigationToLoadEventFired.Background";
+const char kHistogramLoadEventFiredSuffix[] =
+    "DocumentTiming.NavigationToLoadEventFired";
+const char kHistogramParseBlockedOnScriptLoadSuffix[] =
+    "ParseTiming.ParseBlockedOnScriptLoad";
+const char kHistogramParseDurationSuffix[] = "ParseTiming.ParseDuration";
+const char kHistogramParseStartSuffix[] = "ParseTiming.NavigationToParseStart";
+
+}  // namespace internal

chrome/browser/page_load_metrics/observers/histogram_suffixes.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_HISTOGRAM_SUFFIXES_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_HISTOGRAM_SUFFIXES_H_
+
+namespace internal {
+
+// Histogram suffixes used by multiple observers.
+extern const char kHistogramDOMContentLoadedEventFiredBackgroundSuffix[];
+extern const char kHistogramDOMContentLoadedEventFiredSuffix[];
+extern const char kHistogramFirstContentfulPaintSuffix[];
+extern const char kHistogramFirstImagePaintSuffix[];
+extern const char kHistogramFirstLayoutSuffix[];
+extern const char kHistogramFirstMeaningfulPaintSuffix[];
+extern const char kHistogramFirstPaintSuffix[];
+extern const char kHistogramFirstTextPaintSuffix[];
+extern const char kHistogramForegroundToFirstContentfulPaintSuffix[];
+extern const char kHistogramForegroundToFirstMeaningfulPaintSuffix[];
+extern const char kHistogramLoadEventFiredBackgroundSuffix[];
+extern const char kHistogramLoadEventFiredSuffix[];
+extern const char kHistogramParseBlockedOnScriptLoadSuffix[];
+extern const char kHistogramParseDurationSuffix[];
+extern const char kHistogramParseStartSuffix[];
+
+}  // namespace internal
+
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_HISTOGRAM_SUFFIXES_H_

chrome/browser/page_load_metrics/observers/multi_tab_loading_page_load_metrics_observer.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/page_load_metrics/observers/multi_tab_loading_page_load_metrics_observer.h"
 
 #include "base/metrics/histogram_macros.h"
+#include "chrome/browser/page_load_metrics/observers/histogram_suffixes.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "content/public/browser/web_contents.h"
 
@@ -19,32 +20,15 @@
 
 namespace internal {
 
+const char kHistogramPrefixMultiTabLoading[] =
+    "PageLoad.Clients.MultiTabLoading.";
+const char kHistogramPrefixMultiTabLoading2OrMore[] =
+    "PageLoad.Clients.MultiTabLoading.2OrMore.";
+const char kHistogramPrefixMultiTabLoading5OrMore[] =
+    "PageLoad.Clients.MultiTabLoading.5OrMore.";
+
 const char kHistogramMultiTabLoadingNumTabsWithInflightLoad[] =
     "PageLoad.Clients.MultiTabLoading.NumTabsWithInflightLoad";
-const char kHistogramMultiTabLoadingFirstContentfulPaint[] =
-    "PageLoad.Clients.MultiTabLoading.PaintTiming."
-    "NavigationToFirstContentfulPaint";
-const char kHistogramMultiTabLoadingForegroundToFirstContentfulPaint[] =
-    "PageLoad.Clients.MultiTabLoading.PaintTiming."
-    "ForegroundToFirstContentfulPaint";
-const char kHistogramMultiTabLoadingFirstMeaningfulPaint[] =
-    "PageLoad.Clients.MultiTabLoading.Experimental.PaintTiming."
-    "NavigationToFirstMeaningfulPaint";
-const char kHistogramMultiTabLoadingForegroundToFirstMeaningfulPaint[] =
-    "PageLoad.Clients.MultiTabLoading.Experimental.PaintTiming."
-    "ForegroundToFirstMeaningfulPaint";
-const char kHistogramMultiTabLoadingDomContentLoaded[] =
-    "PageLoad.Clients.MultiTabLoading.DocumentTiming."
-    "NavigationToDOMContentLoadedEventFired";
-const char kBackgroundHistogramMultiTabLoadingDomContentLoaded[] =
-    "PageLoad.Clients.MultiTabLoading.DocumentTiming."
-    "NavigationToDOMContentLoadedEventFired.Background";
-const char kHistogramMultiTabLoadingLoad[] =
-    "PageLoad.Clients.MultiTabLoading.DocumentTiming."
-    "NavigationToLoadEventFired";
-const char kBackgroundHistogramMultiTabLoadingLoad[] =
-    "PageLoad.Clients.MultiTabLoading.DocumentTiming."
-    "NavigationToLoadEventFired.Background";
 
 }  // namespace internal
 
@@ -76,19 +60,39 @@ MultiTabLoadingPageLoadMetricsObserver::OnCommit(
                                             : STOP_OBSERVING;
 }
 
+#define RECORD_HISTOGRAMS(suffix, sample)                                      \
+  do {                                                                         \
+    base::TimeDelta sample_value(sample);                                      \
+    PAGE_LOAD_HISTOGRAM(                                                       \
+        std::string(internal::kHistogramPrefixMultiTabLoading).append(suffix), \
+        sample_value);                                                         \
+    if (num_loading_tabs_when_started_ >= 2) {                                 \
+      PAGE_LOAD_HISTOGRAM(                                                     \
+          std::string(internal::kHistogramPrefixMultiTabLoading2OrMore)        \
+              .append(suffix),                                                 \
+          sample_value);                                                       \
+    }                                                                          \
+    if (num_loading_tabs_when_started_ >= 5) {                                 \
+      PAGE_LOAD_HISTOGRAM(                                                     \
+          std::string(internal::kHistogramPrefixMultiTabLoading5OrMore)        \
+              .append(suffix),                                                 \
+          sample_value);                                                       \
+    }                                                                          \
+  } while (false)
+
 void MultiTabLoadingPageLoadMetricsObserver::OnFirstContentfulPaintInPage(
     const page_load_metrics::mojom::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
   if (WasStartedInForegroundOptionalEventInForeground(
           timing.paint_timing->first_contentful_paint, info)) {
-    PAGE_LOAD_HISTOGRAM(internal::kHistogramMultiTabLoadingFirstContentfulPaint,
-                        timing.paint_timing->first_contentful_paint.value());
+    RECORD_HISTOGRAMS(internal::kHistogramFirstContentfulPaintSuffix,
+                      timing.paint_timing->first_contentful_paint.value());
   }
 
   if (WasStartedInBackgroundOptionalEventInForeground(
           timing.paint_timing->first_contentful_paint, info)) {
-    PAGE_LOAD_HISTOGRAM(
-        internal::kHistogramMultiTabLoadingForegroundToFirstContentfulPaint,
+    RECORD_HISTOGRAMS(
+        internal::kHistogramForegroundToFirstContentfulPaintSuffix,
         timing.paint_timing->first_contentful_paint.value() -
             info.first_foreground_time.value());
   }
@@ -100,13 +104,13 @@ void MultiTabLoadingPageLoadMetricsObserver::
         const page_load_metrics::PageLoadExtraInfo& info) {
   if (WasStartedInForegroundOptionalEventInForeground(
           timing.paint_timing->first_meaningful_paint, info)) {
-    PAGE_LOAD_HISTOGRAM(internal::kHistogramMultiTabLoadingFirstMeaningfulPaint,
-                        timing.paint_timing->first_meaningful_paint.value());
+    RECORD_HISTOGRAMS(internal::kHistogramFirstMeaningfulPaintSuffix,
+                      timing.paint_timing->first_meaningful_paint.value());
   }
   if (WasStartedInBackgroundOptionalEventInForeground(
           timing.paint_timing->first_meaningful_paint, info)) {
-    PAGE_LOAD_HISTOGRAM(
-        internal::kHistogramMultiTabLoadingForegroundToFirstMeaningfulPaint,
+    RECORD_HISTOGRAMS(
+        internal::kHistogramForegroundToFirstMeaningfulPaintSuffix,
         timing.paint_timing->first_meaningful_paint.value() -
             info.first_foreground_time.value());
   }
@@ -117,12 +121,12 @@ void MultiTabLoadingPageLoadMetricsObserver::OnDomContentLoadedEventStart(
     const page_load_metrics::PageLoadExtraInfo& info) {
   if (WasStartedInForegroundOptionalEventInForeground(
           timing.document_timing->dom_content_loaded_event_start, info)) {
-    PAGE_LOAD_HISTOGRAM(
-        internal::kHistogramMultiTabLoadingDomContentLoaded,
+    RECORD_HISTOGRAMS(
+        internal::kHistogramDOMContentLoadedEventFiredSuffix,
         timing.document_timing->dom_content_loaded_event_start.value());
   } else {
-    PAGE_LOAD_HISTOGRAM(
-        internal::kBackgroundHistogramMultiTabLoadingDomContentLoaded,
+    RECORD_HISTOGRAMS(
+        internal::kHistogramDOMContentLoadedEventFiredBackgroundSuffix,
         timing.document_timing->dom_content_loaded_event_start.value());
   }
 }
@@ -132,11 +136,11 @@ void MultiTabLoadingPageLoadMetricsObserver::OnLoadEventStart(
     const page_load_metrics::PageLoadExtraInfo& info) {
   if (WasStartedInForegroundOptionalEventInForeground(
           timing.document_timing->load_event_start, info)) {
-    PAGE_LOAD_HISTOGRAM(internal::kHistogramMultiTabLoadingLoad,
-                        timing.document_timing->load_event_start.value());
+    RECORD_HISTOGRAMS(internal::kHistogramLoadEventFiredSuffix,
+                      timing.document_timing->load_event_start.value());
   } else {
-    PAGE_LOAD_HISTOGRAM(internal::kBackgroundHistogramMultiTabLoadingLoad,
-                        timing.document_timing->load_event_start.value());
+    RECORD_HISTOGRAMS(internal::kHistogramLoadEventFiredBackgroundSuffix,
+                      timing.document_timing->load_event_start.value());
   }
 }
 

chrome/browser/page_load_metrics/observers/multi_tab_loading_page_load_metrics_observer.h

@@ -15,15 +15,10 @@ class NavigationHandle;
 namespace internal {
 
 // Exposed for tests.
+extern const char kHistogramPrefixMultiTabLoading[];
+extern const char kHistogramPrefixMultiTabLoading2OrMore[];
+extern const char kHistogramPrefixMultiTabLoading5OrMore[];
 extern const char kHistogramMultiTabLoadingNumTabsWithInflightLoad[];
-extern const char kHistogramMultiTabLoadingFirstContentfulPaint[];
-extern const char kHistogramMultiTabLoadingForegroundToFirstContentfulPaint[];
-extern const char kHistogramMultiTabLoadingFirstMeaningfulPaint[];
-extern const char kHistogramMultiTabLoadingForegroundToFirstMeaningfulPaint[];
-extern const char kHistogramMultiTabLoadingDomContentLoaded[];
-extern const char kBackgroundHistogramMultiTabLoadingDomContentLoaded[];
-extern const char kHistogramMultiTabLoadingLoad[];
-extern const char kBackgroundHistogramMultiTabLoadingLoad[];
 
 }  // namespace internal
 

chrome/browser/page_load_metrics/observers/multi_tab_loading_page_load_metrics_observer_browsertest.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/page_load_metrics/observers/multi_tab_loading_page_load_metrics_observer.h"
 
 #include "base/test/histogram_tester.h"
+#include "chrome/browser/page_load_metrics/observers/histogram_suffixes.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/test/base/in_process_browser_test.h"
@@ -31,6 +32,11 @@ class MultiTabLoadingPageLoadMetricsBrowserTest : public InProcessBrowserTest {
   void SetUpOnMainThread() override {
     ASSERT_TRUE(embedded_test_server()->Start());
   }
+
+  std::string HistogramNameWithSuffix(const char* suffix) {
+    return std::string(internal::kHistogramPrefixMultiTabLoading)
+        .append(suffix);
+  }
 };
 
 IN_PROC_BROWSER_TEST_F(MultiTabLoadingPageLoadMetricsBrowserTest, SingleTab) {
@@ -41,9 +47,12 @@ IN_PROC_BROWSER_TEST_F(MultiTabLoadingPageLoadMetricsBrowserTest, SingleTab) {
   // Navigate away to force the histogram recording.
   ui_test_utils::NavigateToURL(browser(), GURL(url::kAboutBlankURL));
 
-  histogram_tester.ExpectTotalCount(internal::kHistogramMultiTabLoadingLoad, 0);
   histogram_tester.ExpectTotalCount(
-      internal::kBackgroundHistogramMultiTabLoadingLoad, 0);
+      HistogramNameWithSuffix(internal::kHistogramLoadEventFiredSuffix), 0);
+  histogram_tester.ExpectTotalCount(
+      HistogramNameWithSuffix(
+          internal::kHistogramLoadEventFiredBackgroundSuffix),
+      0);
 }
 
 IN_PROC_BROWSER_TEST_F(MultiTabLoadingPageLoadMetricsBrowserTest,
@@ -60,9 +69,12 @@ IN_PROC_BROWSER_TEST_F(MultiTabLoadingPageLoadMetricsBrowserTest,
   // Navigate away to force the histogram recording.
   ui_test_utils::NavigateToURL(browser(), GURL(url::kAboutBlankURL));
 
-  histogram_tester.ExpectTotalCount(internal::kHistogramMultiTabLoadingLoad, 1);
   histogram_tester.ExpectTotalCount(
-      internal::kBackgroundHistogramMultiTabLoadingLoad, 0);
+      HistogramNameWithSuffix(internal::kHistogramLoadEventFiredSuffix), 1);
+  histogram_tester.ExpectTotalCount(
+      HistogramNameWithSuffix(
+          internal::kHistogramLoadEventFiredBackgroundSuffix),
+      0);
 }
 
 IN_PROC_BROWSER_TEST_F(MultiTabLoadingPageLoadMetricsBrowserTest,
@@ -87,7 +99,10 @@ IN_PROC_BROWSER_TEST_F(MultiTabLoadingPageLoadMetricsBrowserTest,
   // Navigate away to force the histogram recording.
   ui_test_utils::NavigateToURL(browser(), GURL(url::kAboutBlankURL));
 
-  histogram_tester.ExpectTotalCount(internal::kHistogramMultiTabLoadingLoad, 0);
   histogram_tester.ExpectTotalCount(
-      internal::kBackgroundHistogramMultiTabLoadingLoad, 1);
+      HistogramNameWithSuffix(internal::kHistogramLoadEventFiredSuffix), 0);
+  histogram_tester.ExpectTotalCount(
+      HistogramNameWithSuffix(
+          internal::kHistogramLoadEventFiredBackgroundSuffix),
+      1);
 }

tools/metrics/histograms/histograms.xml

@@ -106697,6 +106697,12 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <suffix name="Clients.MultiTabLoading"
       label="PageLoadMetrics for page loads that started while there are
              other loading tabs."/>
+  <suffix name="Clients.MultiTabLoading.2OrMore"
+      label="PageLoadMetrics for page loads that started while there are 2 or
+             more other loading tabs."/>
+  <suffix name="Clients.MultiTabLoading.5OrMore"
+      label="PageLoadMetrics for page loads that started while there are 5 or
+             more other loading tabs."/>
   <affected-histogram
       name="PageLoad.DocumentTiming.NavigationToDOMContentLoadedEventFired"/>
   <affected-histogram