gpu: Add YCbCr 420v extension.

ui/gl/test/gl_image_test_support.h

Index: ui/gl/test/gl_image_test_support.h
diff --git a/ui/gl/test/gl_image_test_support.h b/ui/gl/test/gl_image_test_support.h
index 81d67b904007554ab59025163b46f6c08efe0d28..b79618ae1479b6b33efc2b50b64f50a4299012f1 100644
--- a/ui/gl/test/gl_image_test_support.h
+++ b/ui/gl/test/gl_image_test_support.h
@@ -18,7 +18,17 @@ class GLImageTestSupport {
   // Cleanup GL after being initialized for image testing.
   static void CleanupGL();
 
+  // Initialize buffers of a specific |format| to |color|.
+  static void SetBufferDataToColor(int width,
+                                   int height,
+                                   int strides[],
+                                   BufferFormat format,
+                                   const uint8_t color[4],
+                                   uint8_t* data[]);

[reveman, 2015/10/29 22:08:04]

Let's pass a plane argument to this function instead as discussed. I think that
will also eliminate the need for the helper function below.

[Daniele Castagna, 2015/10/30 23:51:57]

Done.

+
   // Initialize buffer of a specific |format| to |color|.
+  // This is useful for GpuMemoryBuffer formats with only
+  // one plane.
   static void SetBufferDataToColor(int width,
                                    int height,
                                    int stride,