Fix ReadPixels implementation specific read format/type on desktop GL.

gpu/command_buffer/common/gles2_cmd_utils_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
 // gpu/command_buffer/build_gles2_cmd_buffer.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 4157 matching lines @@
   };
   return GLES2Util::GetQualifiedEnumString(string_table,
                                            arraysize(string_table), value);
 }
 
 std::string GLES2Util::GetStringReadPixelFormat(uint32_t value) {
   static const EnumToString string_table[] = {
       {GL_ALPHA, "GL_ALPHA"},
       {GL_RGB, "GL_RGB"},
       {GL_RGBA, "GL_RGBA"},
+      {GL_RED, "GL_RED"},
+      {GL_RED_INTEGER, "GL_RED_INTEGER"},
+      {GL_RG, "GL_RG"},
+      {GL_RG_INTEGER, "GL_RG_INTEGER"},
+      {GL_RGB_INTEGER, "GL_RGB_INTEGER"},
       {GL_RGBA_INTEGER, "GL_RGBA_INTEGER"},
   };
   return GLES2Util::GetQualifiedEnumString(string_table,
                                            arraysize(string_table), value);
 }
 
 std::string GLES2Util::GetStringReadPixelType(uint32_t value) {
   static const EnumToString string_table[] = {
       {GL_UNSIGNED_BYTE, "GL_UNSIGNED_BYTE"},
       {GL_UNSIGNED_SHORT_5_6_5, "GL_UNSIGNED_SHORT_5_6_5"},
       {GL_UNSIGNED_SHORT_4_4_4_4, "GL_UNSIGNED_SHORT_4_4_4_4"},
       {GL_UNSIGNED_SHORT_5_5_5_1, "GL_UNSIGNED_SHORT_5_5_5_1"},
+      {GL_BYTE, "GL_BYTE"},
+      {GL_UNSIGNED_SHORT, "GL_UNSIGNED_SHORT"},
+      {GL_SHORT, "GL_SHORT"},
       {GL_UNSIGNED_INT, "GL_UNSIGNED_INT"},
       {GL_INT, "GL_INT"},
+      {GL_HALF_FLOAT, "GL_HALF_FLOAT"},
       {GL_FLOAT, "GL_FLOAT"},
       {GL_UNSIGNED_INT_2_10_10_10_REV, "GL_UNSIGNED_INT_2_10_10_10_REV"},
   };
   return GLES2Util::GetQualifiedEnumString(string_table,
                                            arraysize(string_table), value);
 }
 
 std::string GLES2Util::GetStringRenderBufferFormat(uint32_t value) {
   static const EnumToString string_table[] = {
       {GL_RGBA4, "GL_RGBA4"},
@@ skipping 590 matching lines @@
 
 std::string GLES2Util::GetStringVertexPointer(uint32_t value) {
   static const EnumToString string_table[] = {
       {GL_VERTEX_ATTRIB_ARRAY_POINTER, "GL_VERTEX_ATTRIB_ARRAY_POINTER"},
   };
   return GLES2Util::GetQualifiedEnumString(string_table,
                                            arraysize(string_table), value);
 }
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_IMPLEMENTATION_AUTOGEN_H_