Buffer cross frame paint timing updates.

chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h

 // Copyright 2015 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_PAGE_LOAD_METRICS_OBSERVER_TEST_HARNESS_H_
 #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"

[Charlie Harrison, 2017/05/30 14:49:07]

clean up includes, I think you only need weak_mock_timer

[Bryan McQuade, 2017/05/30 15:30:22]

done

 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/page_load_metrics/page_load_tracker.h"
+#include "chrome/common/page_load_metrics/test/weak_mock_timer.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/chrome_render_view_host_test_harness.h"
 #include "content/public/test/web_contents_tester.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
 #include "ui/base/page_transition_types.h"
 
 namespace page_load_metrics {
 
 // This class can be used to drive tests of PageLoadMetricsObservers. To hook up
 // an observer, override RegisterObservers and call tracker->AddObserver. This
 // will attach the observer to all main frame navigations.
 class PageLoadMetricsObserverTestHarness
-    : public ChromeRenderViewHostTestHarness {
+    : public ChromeRenderViewHostTestHarness,
+      public WeakMockTimerProvider {
  public:
   PageLoadMetricsObserverTestHarness();
   ~PageLoadMetricsObserverTestHarness() override;
 
   // Helper that fills in any timing fields that MWCO requires but that are
   // currently missing.
   static void PopulateRequiredTimingFields(mojom::PageLoadTiming* inout_timing);
 
   void SetUp() override;
 
@@ skipping 46 matching lines @@
  private:
   base::HistogramTester histogram_tester_;
   MetricsWebContentsObserver* observer_;
 
   DISALLOW_COPY_AND_ASSIGN(PageLoadMetricsObserverTestHarness);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_PAGE_LOAD_METRICS_OBSERVER_TEST_HARNESS_H_