Adding YUVA support for enabling Alpha Playback

cc/draw_quad.cc

Index: cc/draw_quad.cc
diff --git a/cc/draw_quad.cc b/cc/draw_quad.cc
index d1f280665b822aaa403d878bc11f9ef3f2025569..0b695f432340190fb713386f41e1aed84d0bed1b 100644
--- a/cc/draw_quad.cc
+++ b/cc/draw_quad.cc
@@ -14,6 +14,7 @@
 #include "cc/texture_draw_quad.h"
 #include "cc/tile_draw_quad.h"
 #include "cc/yuv_video_draw_quad.h"
+#include "cc/yuva_video_draw_quad.h"
 
 namespace {
 
@@ -80,6 +81,9 @@ scoped_ptr<DrawQuad> DrawQuad::Copy(
     case YUV_VIDEO_CONTENT:
       copy_quad.reset(TypedCopy<YUVVideoDrawQuad>(this));
       break;
+    case YUVA_VIDEO_CONTENT:
+      copy_quad.reset(TypedCopy<YUVAVideoDrawQuad>(this));
+      break;
     case RENDER_PASS:  // RenderPass quads have their own copy() method.
     case INVALID:
       LOG(FATAL) << "Invalid DrawQuad material " << material;