RC: Add a histogram to record late performance measurements.

Bug: 755840
Change-Id: I276f74b89cfaab3b3d45ed1e1d0b335ff6299fae
Reviewed-on: https://chromium-review.googlesource.com/1165853Reviewed-by: Chris Hamilton <chrisha@chromium.org>
Reviewed-by: Robert Kaplow (slow) <rkaplow@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581606}

chrome/browser/resource_coordinator/tab_manager_resource_coordinator_signal_observer.cc

@@ -4,6 +4,7 @@
 
 #include "chrome/browser/resource_coordinator/tab_manager_resource_coordinator_signal_observer.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/resource_coordinator/tab_load_tracker.h"
@@ -82,6 +83,17 @@ void TabManager::ResourceCoordinatorSignalObserver::
         const PageNavigationIdentity& page_navigation_id,
         base::TimeDelta cpu_usage_estimate,
         uint64_t private_footprint_kb_estimate) {
+  auto* page_signal_receiver = PageSignalReceiver::GetInstance();
+  DCHECK_NE(nullptr, page_signal_receiver);
+
+  bool late_notification =
+      page_signal_receiver->GetNavigationIDForWebContents(web_contents) !=
+      page_navigation_id.navigation_id;
+
+  UMA_HISTOGRAM_BOOLEAN(
+      "ResourceCoordinator.Measurement.Memory.LateNotification",
+      late_notification);
+
   // TODO(siggi): Persist the measurement associated to |url|'s site.
 }
 

tools/metrics/histograms/histograms.xml

@@ -82857,6 +82857,15 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="ResourceCoordinator.Measurement.Memory.LateNotification"
+    enum="Boolean">
+  <owner>siggi@chromium.org</owner>
+  <summary>
+    A boolean that measures how often a performance measurement notification
+    arrives at a WebContents that has been re-navigated.
+  </summary>
+</histogram>
+
 <histogram name="ResourceCoordinator.Measurement.Memory.Outcome"
     enum="MemoryMeasurementOutcome">
   <owner>siggi@chromium.org</owner>