Add VP9 decode support to the remoting client.

remoting/proto/video.proto

 // 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.
 
 // Protocol for video messages.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package remoting;
 
 message VideoPacketFormat {
   // Identifies how the image was encoded.
   enum Encoding {
     ENCODING_INVALID = -1;
     ENCODING_VERBATIM = 0;
     ENCODING_ZLIB = 1;
     ENCODING_VP8 = 2;
+    ENCODING_VP9 = 3;
   };
 
   // The encoding used for this image update.
   optional Encoding encoding = 5 [default = ENCODING_INVALID];
 
   // Width and height of the whole screen.
   optional int32 screen_width = 6;
   optional int32 screen_height = 7;
 
   // Horizontal and vertical DPI of the screen. If either of these is zero or
@@ skipping 29 matching lines @@
 
   // The most recent sequence number received from the client on the event
   // channel.
   optional int64 client_sequence_number = 9;
 
   repeated Rect desktop_shape_rects = 10;
 
   // True when |desktop_shape_rects| should be used.
   optional bool use_desktop_shape = 11;
 }