ui: Add RGBX_8888 buffer format.

ui/gl/test/gl_image_test_support.h

 // Copyright 2015 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.
 
 #ifndef UI_GL_TEST_GL_IMAGE_TEST_SUPPORT_H_
 #define UI_GL_TEST_GL_IMAGE_TEST_SUPPORT_H_
 
 #include "ui/gfx/buffer_types.h"
 #include "ui/gl/gl_bindings.h"
 
 namespace gfx {
 
 class GLImageTestSupport {
  public:
   // Initialize GL for image testing.
   static void InitializeGL();
 
   // 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,
                                    int stride,
                                    BufferFormat format,
                                    const uint8_t color[4],
                                    uint8_t* data);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_TEST_GL_IMAGE_TEST_SUPPORT_H_