Aura Window Capture: Ensure capture callback is always run.

content/browser/media/capture/aura_window_capture_machine.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 CONTENT_BROWSER_MEDIA_CAPTURE_AURA_WINDOW_CAPTURE_MACHINE_H_
 #define CONTENT_BROWSER_MEDIA_CAPTURE_AURA_WINDOW_CAPTURE_MACHINE_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 71 matching lines @@
   using CaptureFrameCallback =
       media::ThreadSafeCaptureOracle::CaptureFrameCallback;
 
   // Response callback for cc::Layer::RequestCopyOfOutput().
   void DidCopyOutput(scoped_refptr<media::VideoFrame> video_frame,
                      base::TimeTicks start_time,
                      const CaptureFrameCallback& capture_frame_cb,
                      std::unique_ptr<cc::CopyOutputResult> result);
 
   // A helper which does the real work for DidCopyOutput. Returns true if
-  // succeeded.
+  // succeeded and |capture_frame_cb| will be run at some future point. Returns
+  // false on error, and |capture_frame_cb| should be run by the caller (with
+  // failure status).
   bool ProcessCopyOutputResponse(scoped_refptr<media::VideoFrame> video_frame,
                                  base::TimeTicks start_time,
                                  const CaptureFrameCallback& capture_frame_cb,
                                  std::unique_ptr<cc::CopyOutputResult> result);
 
   // Renders the cursor if needed and then delivers the captured frame.
   static void CopyOutputFinishedForVideo(
       base::WeakPtr<AuraWindowCaptureMachine> machine,
       base::TimeTicks start_time,
       const CaptureFrameCallback& capture_frame_cb,
@@ skipping 29 matching lines @@
   // immediately when InternalStop() is called to ensure that no more captured
   // frames will be delivered to the client.
   base::WeakPtrFactory<AuraWindowCaptureMachine> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AuraWindowCaptureMachine);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_CAPTURE_AURA_WINDOW_CAPTURE_MACHINE_H_