command_buffer: Implement CHROMIUM_framebuffer_mixed_samples extension

ui/gl/gl_enums_implementation_autogen.h

 // Copyright 2014 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 is auto-generated from
 // ui/gl/generate_bindings.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 793 matching lines @@
     {
         0x9283, "GL_DISJOINT_NV",
     },
     {
         0x8221, "GL_PRIMITIVE_RESTART_FOR_PATCHES_SUPPORTED",
     },
     {
         0x8227, "GL_RG_EXT",
     },
     {
+        0x9332, "GL_COVERAGE_MODULATION_CHROMIUM",
+    },
+    {
         0x8B66, "GL_FLOAT_MAT2x4_NV",
     },
     {
         0x8B67, "GL_FLOAT_MAT3x2_NV",
     },
     {
         0x8E1E, "GL_MAX_COMBINED_TESS_CONTROL_UNIFORM_COMPONENTS_EXT",
     },
     {
         0x8B62, "GL_SAMPLER_2D_SHADOW_EXT",
@@ skipping 2622 matching lines @@
     },
     {
         0x8BC6, "GL_PERFMON_RESULT_AMD",
     },
 };
 
 const GLEnums::EnumToString* const GLEnums::enum_to_string_table_ =
     enum_to_string_table;
 const size_t GLEnums::enum_to_string_table_len_ =
     sizeof(enum_to_string_table) / sizeof(enum_to_string_table[0]);