ui: Add RGBX_8888 buffer format.

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 782f2075a1c672c3150b783965fabf4183b65272..81d67b904007554ab59025163b46f6c08efe0d28 100644
--- a/ui/gl/test/gl_image_test_support.h
+++ b/ui/gl/test/gl_image_test_support.h
@@ -18,12 +18,6 @@ class GLImageTestSupport {
   // Cleanup GL after being initialized for image testing.
   static void CleanupGL();
 
-  // Returns the preferred internal format used for images.
-  static GLenum GetPreferredInternalFormat();
-
-  // Returns the preferred buffer format used for images.
-  static BufferFormat GetPreferredBufferFormat();
-
   // Initialize buffer of a specific |format| to |color|.
   static void SetBufferDataToColor(int width,
                                    int height,