getUserMeida: report device starting states

content/browser/media/capture/web_contents_video_capture_device_unittest.cc

 // Copyright (c) 2012 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 "content/browser/media/capture/web_contents_video_capture_device.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 304 matching lines @@
       return media::VideoCaptureDevice::Client::Buffer();
     return media::VideoCaptureDeviceClient::MakeBufferStruct(
         buffer_pool_, buffer_id, frame_feedback_id);
   }
 
   void OnError(const tracked_objects::Location& from_here,
                const std::string& reason) override {
     error_callback_.Run();
   }
 
+  void OnStarted() override {}

[miu, 2017/02/09 22:21:49]

Where does WebContentsVideoCaptureDevice call OnStarted()? (It seems to be
missing from this patch.)

[braveyao, 2017/02/14 01:05:49]

It's called in ScreenCaptureDeviceCore::CaptureStarted,
https://codereview.chromium.org/2673373003/diff/20001/media/capture/content/s....
Same to Aura and Tab capture.

+
   double GetBufferPoolUtilization() const override { return 0.0; }
 
  private:
   scoped_refptr<media::VideoCaptureBufferPool> buffer_pool_;
   base::Callback<void(SkColor, const gfx::Size&)> report_callback_;
   base::Closure error_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(StubClient);
 };
 
@@ skipping 674 matching lines @@
   for (int i = 0; i < 3; ++i) {
     SimulateRefreshFrameRequest();
     ASSERT_NO_FATAL_FAILURE(client_observer()->WaitForNextColor(SK_ColorGREEN));
   }
 
   device()->StopAndDeAllocate();
 }
 
 }  // namespace
 }  // namespace content