Reland CL to implement browser-side logging to WebRtc log.

media/video/capture/video_capture_device.h

 // Copyright (c) 2012 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.
 //
 // VideoCaptureDevice is the abstract base class for realizing video capture
 // device support in Chromium. It provides the interface for OS dependent
 // implementations.
 // The class is created and functions are invoked on a thread owned by
 // VideoCaptureManager. Capturing is done on other threads, depending on the OS
 // specific implementation.
@@ skipping 162 matching lines @@
     // additional copies in the browser process. |dimensions| indicates the
     // frame width and height of the buffer contents; this is assumed to be of
     // |format| format and tightly packed.
     virtual void OnIncomingCapturedBuffer(const scoped_refptr<Buffer>& buffer,
                                           media::VideoFrame::Format format,
                                           const gfx::Size& dimensions,
                                           base::TimeTicks timestamp,
                                           int frame_rate) = 0;
 
     // An error has occurred that cannot be handled and VideoCaptureDevice must
-    // be StopAndDeAllocate()-ed.
-    virtual void OnError() = 0;
+    // be StopAndDeAllocate()-ed. |reason| is a text description of the error.
+    virtual void OnError(const std::string& reason) = 0;
   };
 
   // Creates a VideoCaptureDevice object.
   // Return NULL if the hardware is not available.
   static VideoCaptureDevice* Create(const Name& device_name);
   virtual ~VideoCaptureDevice();
 
   // Gets the names of all video capture devices connected to this computer.
   static void GetDeviceNames(Names* device_names);
 
@@ skipping 20 matching lines @@
   // If deallocation is done asynchronously, then the device implementation must
   // ensure that a subsequent AllocateAndStart() operation targeting the same ID
   // would be sequenced through the same task runner, so that deallocation
   // happens first.
   virtual void StopAndDeAllocate() = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_