Fix WebrtcVideoCapturerAdapter to emit frames even when nothing is changing.

remoting/protocol/webrtc_video_capturer_adapter.cc

Index: remoting/protocol/webrtc_video_capturer_adapter.cc
diff --git a/remoting/protocol/webrtc_video_capturer_adapter.cc b/remoting/protocol/webrtc_video_capturer_adapter.cc
index 96c2c3af891e62d8b95a3d18218d3e7920be48ec..c0aeea1a193fe1cca5953777784155ef47c3e01c 100644
--- a/remoting/protocol/webrtc_video_capturer_adapter.cc
+++ b/remoting/protocol/webrtc_video_capturer_adapter.cc
@@ -161,11 +161,16 @@ void WebrtcVideoCapturerAdapter::OnCaptureCompleted(
   DCHECK(capture_pending_);
   capture_pending_ = false;
 
+  if (!frame)
+    return;
+
   scoped_ptr<webrtc::DesktopFrame> owned_frame(frame);
 
-  // Drop the frame if there were no changes.
-  if (!owned_frame || owned_frame->updated_region().is_empty())
-    return;
+  // TODO(sergeyu): Currently the adapter keeps generating frames even when
+  // nothing is changing on the screen. This is necessary because the video
+  // sender drops frames. Obviously this is a suboptimal. The sending code in
+  // WebRTC needs to have some mechanism to notify when the bandwidth is
+  // exceeded, so the capturer can adapt frame rate.
 
   size_t width = frame->size().width();
   size_t height = frame->size().height();