Buffer cross frame paint timing updates.

chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h

Index: chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h
diff --git a/chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h b/chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h
index 5d4cd7daacc48baf76cdcf207707240323f5dc9d..5850f9b8262f0692a5ab1ddfc86839d92e664c9e 100644
--- a/chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h
+++ b/chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h
@@ -6,7 +6,9 @@
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_PAGE_LOAD_METRICS_OBSERVER_TEST_HARNESS_H_
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/test/histogram_tester.h"
+#include "base/timer/mock_timer.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/page_load_metrics/page_load_tracker.h"
 #include "chrome/common/url_constants.h"
@@ -23,6 +25,13 @@ namespace page_load_metrics {
 class PageLoadMetricsObserverTestHarness
     : public ChromeRenderViewHostTestHarness {
  public:
+  class WeakMockTimer : public base::MockTimer,
+                        public base::SupportsWeakPtr<WeakMockTimer> {
+   public:
+    WeakMockTimer()
+        : MockTimer(false /* retain_user_task */, false /* is_repeating */) {}
+  };
+
   PageLoadMetricsObserverTestHarness();
   ~PageLoadMetricsObserverTestHarness() override;
 
@@ -78,9 +87,17 @@ class PageLoadMetricsObserverTestHarness
   // Gets the PageLoadExtraInfo for the committed_load_ in observer_.
   const PageLoadExtraInfo GetPageLoadExtraInfoForCommittedLoad();
 
+  // Gets the timer most recently created by the
+  // PageLoadMetricsEmbedderInterface.
+  base::MockTimer* GetMostRecentTimer() { return most_recent_timer_.get(); }
+  void SetMostRecentTimer(base::WeakPtr<WeakMockTimer> timer) {
+    most_recent_timer_ = timer;
+  }
+
  private:
   base::HistogramTester histogram_tester_;
   MetricsWebContentsObserver* observer_;
+  base::WeakPtr<WeakMockTimer> most_recent_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(PageLoadMetricsObserverTestHarness);
 };