Aura Window Capture: Ensure capture callback is always run.

The capture callback must always be run, or eventually the capture
decision logic will think there are too many captures in-flight.  This
closes some "holes" in content::AuraWindowCaptureMachine where methods
exit early without running the callback.  This is a potential fix for
crbug 600031.

BUG=600031

Review URL: https://codereview.chromium.org/1913283004

Cr-Commit-Position: refs/heads/master@{#389867}

content/browser/media/capture/aura_window_capture_machine.cc

@@ -199,7 +199,7 @@ void AuraWindowCaptureMachine::DidCopyOutput(
 
   static bool first_call = true;
 
-  bool succeeded = ProcessCopyOutputResponse(
+  const bool succeeded = ProcessCopyOutputResponse(
       video_frame, start_time, capture_frame_cb, std::move(result));
 
   base::TimeDelta capture_time = base::TimeTicks::Now() - start_time;
@@ -223,6 +223,11 @@ void AuraWindowCaptureMachine::DidCopyOutput(
                                          : FIRST_WINDOW_CAPTURE_FAILED);
     }
   }
+
+  // If ProcessCopyOutputResponse() failed, it will not run |capture_frame_cb|,
+  // so do that now.
+  if (!succeeded)
+    capture_frame_cb.Run(video_frame, start_time, false);
 }
 
 bool AuraWindowCaptureMachine::ProcessCopyOutputResponse(
@@ -310,8 +315,11 @@ void AuraWindowCaptureMachine::CopyOutputFinishedForVideo(
   if (machine) {
     if (machine->cursor_renderer_ && result)
       machine->cursor_renderer_->RenderOnVideoFrame(target);
-    capture_frame_cb.Run(target, start_time, result);
+  } else {
+    result = false;
   }
+
+  capture_frame_cb.Run(target, start_time, result);
 }
 
 void AuraWindowCaptureMachine::OnWindowBoundsChanged(

content/browser/media/capture/aura_window_capture_machine.h

@@ -89,7 +89,9 @@ class AuraWindowCaptureMachine
                      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,

media/capture/content/thread_safe_capture_oracle.cc

@@ -141,8 +141,15 @@ bool ThreadSafeCaptureOracle::ObserveEventAndDecideCapture(
       static_cast<uint8_t*>(output_buffer->data()),
       output_buffer->mapped_size(), base::SharedMemory::NULLHandle(), 0u,
       base::TimeDelta());
-  if (!(*storage))
+  // If creating the VideoFrame wrapper failed, call DidCaptureFrame() with
+  // !success to execute the required post-capture steps (tracing, notification
+  // of failure to VideoCaptureOracle, etc.).
+  if (!(*storage)) {
+    DidCaptureFrame(frame_number, std::move(output_buffer), capture_begin_time,
+                    estimated_frame_duration, *storage, event_time, false);
     return false;
+  }
+
   *callback = base::Bind(&ThreadSafeCaptureOracle::DidCaptureFrame, this,
                          frame_number, base::Passed(&output_buffer),
                          capture_begin_time, estimated_frame_duration);

media/capture/content/thread_safe_capture_oracle.h

@@ -48,9 +48,10 @@ class MEDIA_EXPORT ThreadSafeCaptureOracle
   // resources.
   //
   // If this method returns false, the caller should take no further action.
-  // Otherwise, |storage| is set to the destination for the video frame capture;
-  // and, the caller should initiate capture, and then run |callback| once the
-  // video frame has been populated with its content.
+  // Otherwise, |storage| is set to the destination for the video frame capture
+  // and the caller should initiate capture.  Then, once the video frame has
+  // been populated with its content, or if capture failed, the |callback|
+  // should be run.
   bool ObserveEventAndDecideCapture(VideoCaptureOracle::Event event,
                                     const gfx::Rect& damage_rect,
                                     base::TimeTicks event_time,