Fix DCHECK error when invalid video constraints are set on gUM. If a video constraint can not be me…

content/renderer/media/media_stream_video_capturer_source.cc

 // Copyright 2014 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/renderer/media/media_stream_video_capturer_source.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "content/renderer/media/video_capture_impl_manager.h"
 #include "content/renderer/render_thread_impl.h"
@@ skipping 26 matching lines @@
     const StreamDeviceInfo& device_info)
     : session_id_(device_info.session_id),
       capture_engine_(
           RenderThreadImpl::current()->video_capture_impl_manager()
               ->UseDevice(device_info.session_id)),
       is_screen_cast_(device_info.device.type == MEDIA_TAB_VIDEO_CAPTURE ||
                       device_info.device.type == MEDIA_DESKTOP_VIDEO_CAPTURE),
       got_first_frame_(false) {
   DVLOG(3) << "VideoCapturerDelegate::ctor";
   DCHECK(capture_engine_);
+  message_loop_proxy_ = base::MessageLoopProxy::current();
 }
 
 VideoCapturerDelegate::~VideoCapturerDelegate() {
   DVLOG(3) << "VideoCapturerDelegate::dtor";
   DCHECK(new_frame_callback_.is_null());
 }
 
 void VideoCapturerDelegate::GetCurrentSupportedFormats(
     int max_requested_width,
     int max_requested_height,
@@ skipping 29 matching lines @@
             media::PIXEL_FORMAT_I420));
   }
   callback.Run(formats);
 }
 
 void VideoCapturerDelegate::StartDeliver(
     const media::VideoCaptureParams& params,
     const NewFrameCallback& new_frame_callback,
     const StartedCallback& started_callback) {
   DCHECK(params.requested_format.IsValid());
-  message_loop_proxy_ = base::MessageLoopProxy::current();
+  DCHECK(message_loop_proxy_ == base::MessageLoopProxy::current());
   new_frame_callback_ = new_frame_callback;
   started_callback_ = started_callback;
   got_first_frame_ = false;
 
   // Increase the reference count to ensure the object is not deleted until
   // it is unregistered in VideoCapturerDelegate::OnRemoved.
   AddRef();
   capture_engine_->StartCapture(this, params);
 }
 
@@ skipping 10 matching lines @@
   DVLOG(3) << "VideoCapturerDelegate::OnStarted";
 }
 
 void VideoCapturerDelegate::OnStopped(media::VideoCapture* capture) {
 }
 
 void VideoCapturerDelegate::OnPaused(media::VideoCapture* capture) {
 }
 
 void VideoCapturerDelegate::OnError(media::VideoCapture* capture,
-                                             int error_code) {
+                                    int error_code) {
   DVLOG(3) << "VideoCapturerDelegate::OnError";
   message_loop_proxy_->PostTask(
       FROM_HERE,
       base::Bind(&VideoCapturerDelegate::OnErrorOnCaptureThread,
                  this, capture));
 }
 
 void VideoCapturerDelegate::OnRemoved(media::VideoCapture* capture) {
   DVLOG(3) << " MediaStreamVideoCapturerSource::OnRemoved";
 
@@ skipping 66 matching lines @@
                  base::Unretained(this)),
       base::Bind(&MediaStreamVideoCapturerSource::OnStartDone,
                  base::Unretained(this)));
 }
 
 void MediaStreamVideoCapturerSource::StopSourceImpl() {
   delegate_->StopDeliver();
 }
 
 }  // namespace content