ppapi: make gl2ext.h values consistent with third_party/khronos/GLES2/gl2ext.h

ppapi/lib/gl/include/GLES2/gl2ext.h

 #ifndef __gl2ext_h_
 #define __gl2ext_h_
 
 /* $Revision: 16619 $ on $Date:: 2012-01-18 10:00:14 -0800 #$ */
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /*
@@ skipping 292 matching lines @@
 /* GL_EXT_discard_framebuffer */
 #ifndef GL_EXT_discard_framebuffer
 #define GL_COLOR_EXT                                            0x1800
 #define GL_DEPTH_EXT                                            0x1801
 #define GL_STENCIL_EXT                                          0x1802
 #endif
 
 /* GL_EXT_multisampled_render_to_texture */
 #ifndef GL_EXT_multisampled_render_to_texture
 #define GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_SAMPLES_EXT           0x8D6C
-#define GL_RENDERBUFFER_SAMPLES_EXT                             0x9133
-#define GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT               0x9134
-#define GL_MAX_SAMPLES_EXT                                      0x9135
+#define GL_RENDERBUFFER_SAMPLES_EXT                             0x8CAB
+#define GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT               0x8D56
+#define GL_MAX_SAMPLES_EXT                                      0x8D57
 #endif
 
 /* GL_EXT_multi_draw_arrays */
 /* No new tokens introduced by this extension. */
 
 /* GL_EXT_occlusion_query_boolean */
 #ifndef GL_EXT_occlusion_query_boolean
 #define GL_ANY_SAMPLES_PASSED_EXT                               0x8C2F
 #define GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT                  0x8D6A
 #define GL_CURRENT_QUERY_EXT                                    0x8865
@@ skipping 1655 matching lines @@
 #define GL_CHROMIUM_command_buffer_query 1
 // TODO(gman): Get official numbers for these constants.
 #define GL_COMMANDS_ISSUED_CHROMIUM 0x84F2
 #endif
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* __gl2ext_h_ */