Allow MediaStream constraints to specify higher than 30 FPS tab capture.

content/renderer/media/mock_media_stream_video_source.h

Index: content/renderer/media/mock_media_stream_video_source.h
diff --git a/content/renderer/media/mock_media_stream_video_source.h b/content/renderer/media/mock_media_stream_video_source.h
index 0786798789c042fa3f3d6ed405f4a9676bdc0e06..449adbd4a57c0a7fb20eb7e07df3a95edc94707d 100644
--- a/content/renderer/media/mock_media_stream_video_source.h
+++ b/content/renderer/media/mock_media_stream_video_source.h
@@ -42,6 +42,7 @@ class MockMediaStreamVideoSource : public MediaStreamVideoSource {
   const media::VideoCaptureParams& start_params() const { return params_; }
   int max_requested_height() const { return max_requested_height_; }
   int max_requested_width() const { return max_requested_width_; }
+  double max_requested_frame_rate() const { return max_requested_frame_rate_; }
 
   void SetMutedState(bool muted_state) {
     MediaStreamVideoSource::SetMutedState(muted_state);
@@ -58,6 +59,7 @@ class MockMediaStreamVideoSource : public MediaStreamVideoSource {
   virtual void GetCurrentSupportedFormats(
       int max_requested_height,
       int max_requested_width,
+      double max_requested_frame_rate,
       const VideoCaptureDeviceFormatsCB& callback) OVERRIDE;
   virtual void StartSourceImpl(
       const media::VideoCaptureParams& params,
@@ -70,6 +72,7 @@ class MockMediaStreamVideoSource : public MediaStreamVideoSource {
   bool manual_get_supported_formats_;
   int max_requested_height_;
   int max_requested_width_;
+  double max_requested_frame_rate_;
   bool attempted_to_start_;
   VideoCaptureDeviceFormatsCB formats_callback_;
   VideoCaptureDeliverFrameCB frame_callback_;