VideoCaptureFormat: add method to print out pixel format as string

content/renderer/media/media_stream_video_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_source.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 452 matching lines @@
     // This object can be deleted after calling FinalizeAddTrack. See comment
     // in the header file.
     FinalizeAddTrack();
     return;
   }
 
   state_ = STARTING;
   DVLOG(3) << "Starting the capturer with"
            << " width = " << current_format_.frame_size.width()
            << " height = " << current_format_.frame_size.height()
-           << " frame rate = " << current_format_.frame_rate;
+           << " frame rate = " << current_format_.frame_rate
+           << " pixel format = "
+           << media::VideoCaptureFormat::PixelFormatToString(
+               current_format_.pixel_format);
 
   media::VideoCaptureParams params;
   params.requested_format = current_format_;
   StartSourceImpl(
       params,
       base::Bind(&VideoTrackAdapter::DeliverFrameOnIO, track_adapter_));
 }
 
 bool MediaStreamVideoSource::FindBestFormatWithConstraints(
     const media::VideoCaptureFormats& formats,
@@ skipping 123 matching lines @@
     : track(track),
       frame_callback(frame_callback),
       constraints(constraints),
       callback(callback) {
 }
 
 MediaStreamVideoSource::RequestedConstraints::~RequestedConstraints() {
 }
 
 }  // namespace content