Use std::unique_ptr<> to pass frame ownership in DesktopCapturer impls.

webrtc/modules/desktop_capture/screen_capturer_mock_objects.h

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 18 matching lines @@
 
  private:
   RTC_DISALLOW_COPY_AND_ASSIGN(MockScreenCapturer);
 };
 
 class MockScreenCapturerCallback : public ScreenCapturer::Callback {
  public:
   MockScreenCapturerCallback() {}
   virtual ~MockScreenCapturerCallback() {}
 
-  MOCK_METHOD1(OnCaptureCompleted, void(DesktopFrame*));
+  MOCK_METHOD1(OnCaptureCompletedPtr,
+               void(std::unique_ptr<DesktopFrame>* frame));

[Wez, 2016/05/18 01:29:50]

In our other tests we un-wrap the |frame| so that this would be DesktopFrame* -
what's the rationale for passing unique_ptr<>* instead?

[Sergey Ulanov, 2016/05/31 12:02:48]

When passing unique_ptr<>* the test doesn't have to delete the frame if it
doesn't need it, which makes the tests simpler. 

[Wez, 2016/06/01 21:29:04]

Ah, very nice. Sounds like we should follow this pattern in new tests in place
of the old bare-pointer approach.

+  void OnCaptureCompleted(std::unique_ptr<DesktopFrame> frame) override {
+    OnCaptureCompletedPtr(&frame);
+  }
 
  private:
   RTC_DISALLOW_COPY_AND_ASSIGN(MockScreenCapturerCallback);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_MOCK_OBJECTS_H_