Add MediaControlsImplTestWithMockScheduler.

third_party/WebKit/Source/modules/media_controls/MediaControlsImplTest.cpp

 // 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.
 
 #include "modules/media_controls/MediaControlsImpl.h"
 
 #include <limits>
 #include <memory>
 #include "core/HTMLNames.h"
 #include "core/css/StylePropertySet.h"
@@ skipping 133 matching lines @@
 
     GetDocument().write("<video>");
     HTMLVideoElement& video =
         toHTMLVideoElement(*GetDocument().QuerySelector("video"));
     media_controls_ = static_cast<MediaControlsImpl*>(video.GetMediaControls());
 
     // If scripts are not enabled, controls will always be shown.
     page_holder_->GetFrame().GetSettings()->SetScriptEnabled(true);
   }
 
+  void ResetPage() { page_holder_.reset(); }
+
   void SimulateRouteAvailable() {
     media_controls_->MediaElement().RemoteRouteAvailabilityChanged(
         WebRemotePlaybackAvailability::kDeviceAvailable);
   }
 
   void EnsureSizing() {
     // Fire the size-change callback to ensure that the controls have
     // been properly notified of the video size.
     media_controls_->NotifyElementSizeChanged(
         media_controls_->MediaElement().getBoundingClientRect());
@@ skipping 621 matching lines @@
       "Media.Timeline.DragGestureDuration.128_255", 1);
   GetHistogramTester().ExpectUniqueSample("Media.Timeline.DragPercent.128_255",
                                           8 /* (-35.0%, -30.0%] */, 1);
   GetHistogramTester().ExpectUniqueSample(
       "Media.Timeline.DragSumAbsTimeDelta.128_255", 17 /* [8m, 15m) */, 1);
   GetHistogramTester().ExpectUniqueSample(
       "Media.Timeline.DragTimeDelta.128_255", 9 /* (-4m, -2m] */, 1);
 }
 
 TEST_F(MediaControlsImplTest, ControlsRemainVisibleDuringKeyboardInteraction) {
+  ResetPage();

[whywhat, 2017/05/29 18:19:53]

This is the line that would likely look confusing to anyone reading this code in
a month from now. Hence I asked for a comment here in my previous reply.

Could we avoid the issue by making ScopedTestingPlatformSupport<> a member of
MediaControlsImplTest reset in SetUp() before InitializePage with a new value?

Then it could be exposed as Platform() to the test case below which won't have
to create a scoped platform or InitializePage() hence avoiding the issue with
PerformanceMonitor.

Something like:

...

class MediaControlsImplTest {
  void SetUp() override {
    testing_platform_ =
MakeUnique<ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>>();
    InitializePage();
  }

  ScopedTestingPlatformSupport* Platform() { return testing_platform_.get(); }

  ...

 private:
 
unique_ptr<ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>>
testing_platform_;
  ...
};

...

TEST_F(MediaControlsImplTest, ControlsRemainVisibleDuringKeyboardInteraction) {
  // DocumentParserTiming has DCHECKS to make sure time > 0.0.
  Platform()->AdvanceClockSeconds(1);
  EnsureSizing();

  Element* panel = MediaControls().PanelElement();

  ...
  Platform()->RunForPeriodSeconds(2);
  ...
}

+
   ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>
       platform;
 
   // DocumentParserTiming has DCHECKS to make sure time > 0.0.
   platform->AdvanceClockSeconds(1);
 
   // Need to reinitialize page since we changed the platform.
   InitializePage();
   EnsureSizing();
 
@@ skipping 79 matching lines @@
   {
     Persistent<HTMLMediaElement> video_holder = element;
     page_holder->GetDocument().body()->RemoveChild(element);
     page_holder->GetDocument().body()->AppendChild(video_holder.Get());
     EXPECT_TRUE(remote_playback->HasEventListeners());
     EXPECT_TRUE(HasAvailabilityCallbacks(remote_playback));
   }
 }
 
 }  // namespace blink