New resolution change policies for desktop and tab capture.

content/renderer/media/media_stream_video_source.h

 // 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.
 
 #ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_SOURCE_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_SOURCE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 52 matching lines @@
   static bool IsConstraintSupported(const std::string& name);
 
   // Returns the MessageLoopProxy where video frames will be delivered on.
   const scoped_refptr<base::MessageLoopProxy>& io_message_loop() const;
 
   // Constraint keys used by a video source.
   // Specified by draft-alvestrand-constraints-resolution-00b
   static const char kMinAspectRatio[];  // minAspectRatio
   static const char kMaxAspectRatio[];  // maxAspectRatio
   static const char kMaxWidth[];  // maxWidth
-  static const char kMinWidth[];  // minWidthOnCaptureFormats
+  static const char kMinWidth[];  // minWidth
   static const char kMaxHeight[];  // maxHeight
   static const char kMinHeight[];  // minHeight
   static const char kMaxFrameRate[];  // maxFrameRate
   static const char kMinFrameRate[];  // minFrameRate
 
   enum {
     // Default resolution. If no constraints are specified and the delegate
     // support it, this is the resolution that will be used.
     kDefaultWidth = 640,
     kDefaultHeight = 480,
@@ skipping 16 matching lines @@
   // |max_requested_height| and |max_requested_width| is the max height and
   // width set as a mandatory constraint if set when calling
   // MediaStreamVideoSource::AddTrack. If max height and max width is not set
   // |max_requested_height| and |max_requested_width| are 0.
   virtual void GetCurrentSupportedFormats(
       int max_requested_width,
       int max_requested_height,
       double max_requested_frame_rate,
       const VideoCaptureDeviceFormatsCB& callback) = 0;
 
-  // An implementation must start capture frames using the resolution in
-  // |params|. When the source has started or the source failed to start
-  // OnStartDone must be called. An implementation must call
-  // |frame_callback| on the IO thread with the captured frames.
+  // An implementation must start to capture frames using the requested

[mcasas, 2015/05/07 22:10:00]

s/start to capture/start capturing/? (Disclaimer: English is not my native
language as you know  :) )

+  // |format|. The fulfilled |constraints| are provided as additional context,
+  // and may be used to modify the behavior of the source. When the source has
+  // started or the source failed to start OnStartDone must be called. An
+  // implementation must call |frame_callback| on the IO thread with the
+  // captured frames.
   virtual void StartSourceImpl(
       const media::VideoCaptureFormat& format,
+      const blink::WebMediaConstraints& constraints,
       const VideoCaptureDeliverFrameCB& frame_callback) = 0;
   void OnStartDone(MediaStreamRequestResult result);
 
   // An implementation must immediately stop capture video frames and must not
   // call OnSupportedFormats after this method has been called. After this
   // method has been called, MediaStreamVideoSource may be deleted.
   virtual void StopSourceImpl() = 0;
 
   enum State {
     NEW,
     RETRIEVING_CAPABILITIES,
     STARTING,
     STARTED,
     ENDED
   };
   State state() const { return state_; }
 
  private:
   void OnSupportedFormats(const media::VideoCaptureFormats& formats);
 
   // Finds the first constraints in |requested_constraints_| that can be
   // fulfilled. |best_format| is set to the video resolution that can be
   // fulfilled.

[mcasas, 2015/05/07 22:10:00]

... and |fulfilled_contraints| is the actual result?

[miu, 2015/05/08 06:43:34]

Fixed comment, and added details about the return value.

   bool FindBestFormatWithConstraints(
       const media::VideoCaptureFormats& formats,
-      media::VideoCaptureFormat* best_format);
+      media::VideoCaptureFormat* best_format,
+      blink::WebMediaConstraints* fulfilled_constraints);
 
   // Trigger all cached callbacks from AddTrack. AddTrack is successful
   // if the capture delegate has started and the constraints provided in
   // AddTrack match the format that was used to start the device.
   // Note that it must be ok to delete the MediaStreamVideoSource object
   // in the context of the callback. If gUM fail, the implementation will
   // simply drop the references to the blink source and track which will lead
   // to that this object is deleted.
   void FinalizeAddTrack();
 
@@ skipping 25 matching lines @@
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<MediaStreamVideoSource> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamVideoSource);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_SOURCE_H_