Refactor validation code so it can be modified at runtime....

gpu/command_buffer/service/gl_utils.h

 // Copyright (c) 2009 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.
 
 // This file includes all the necessary GL headers and implements some useful
 // utilities.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GL_UTILS_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GL_UTILS_H_
 
 #include "build/build_config.h"
 #include "app/gfx/gl/gl_bindings.h"
 
 // GLES2 defines not part of Desktop GL
 // Shader Precision-Specified Types
 #define GL_LOW_FLOAT                      0x8DF0
 #define GL_MEDIUM_FLOAT                   0x8DF1
 #define GL_HIGH_FLOAT                     0x8DF2
 #define GL_LOW_INT                        0x8DF3
 #define GL_MEDIUM_INT                     0x8DF4
 #define GL_HIGH_INT                       0x8DF5
 #define GL_IMPLEMENTATION_COLOR_READ_TYPE   0x8B9A
 #define GL_IMPLEMENTATION_COLOR_READ_FORMAT 0x8B9B
 #define GL_MAX_FRAGMENT_UNIFORM_VECTORS     0x8DFD
 #define GL_MAX_VERTEX_UNIFORM_VECTORS       0x8DFB
 #define GL_MAX_VARYING_VECTORS              0x8DFC
 #define GL_SHADER_BINARY_FORMATS          0x8DF8
 #define GL_NUM_SHADER_BINARY_FORMATS      0x8DF9
 #define GL_SHADER_COMPILER                0x8DFA
+#define GL_RGB565                         0x8D62
 
 #define GL_GLEXT_PROTOTYPES 1
 
 // Define this for extra GL error debugging (slower).
 // #define GL_ERROR_DEBUGGING
 #ifdef GL_ERROR_DEBUGGING
 #define CHECK_GL_ERROR() do {                                           \
     GLenum gl_error = glGetError();                                     \
     LOG_IF(ERROR, gl_error != GL_NO_ERROR) << "GL Error :" << gl_error; \
   } while (0)
 #else  // GL_ERROR_DEBUGGING
 #define CHECK_GL_ERROR() void(0)
 #endif  // GL_ERROR_DEBUGGING
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GL_UTILS_H_