Add video-rendering to mojo media pipeline.

media/base/pipeline.h

Index: media/base/pipeline.h
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index db326c2928353f2aa9d6080ad650e4ecd56f22fb..35eee3235fdc8b5108cfa22f2aa085519258673a 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -54,6 +54,8 @@ class MEDIA_EXPORT Pipeline {
   //                 video in supported formats are known.
   //   |buffering_state_cb| will be executed whenever there are changes in the
   //                        overall buffering state of the pipeline.
+  //   |natural_size_changed_cb| will be executed whenever video natural size
+  //                             changes.

[xhwang, 2016/04/12 19:40:37]

Will this be called for the first frame? I feel calling it for the first frame
makes sense because we have a new size). I don't remember what's the historical
magic around the first frame though.

+dalecurtis

[DaleCurtis, 2016/04/12 20:52:42]

The VideoFrameCompositor wants this called for the first frame, without this
Blink may not have the right size information IIRC.

   //   |duration_change_cb| optional callback that will be executed whenever the
   //                        presentation duration changes.
   //   |add_text_track_cb| will be executed whenever a text track is added.
@@ -67,6 +69,7 @@ class MEDIA_EXPORT Pipeline {
                      const PipelineStatusCB& seek_cb,
                      const PipelineMetadataCB& metadata_cb,
                      const BufferingStateCB& buffering_state_cb,
+                     const NaturalSizeChangedCB& natural_size_changed_cb,
                      const base::Closure& duration_change_cb,
                      const AddTextTrackCB& add_text_track_cb,
                      const base::Closure& waiting_for_decryption_key_cb) = 0;