Add EXT_color_buffer_half_float extension support in GPU commandbuffer service.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 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.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 6905 matching lines @@
 
       uint32 unpadded_row_size;
       uint32 padded_row_size;
       if (!GLES2Util::ComputeImageDataSizes(
           width, 2, format, type, state_.pack_alignment, &temp_size,
           &unpadded_row_size, &padded_row_size)) {
         LOCAL_SET_GL_ERROR(
             GL_INVALID_VALUE, "glReadPixels", "dimensions out of range");
         return error::kNoError;
       }
-      // NOTE: Assumes the type is GL_UNSIGNED_BYTE which was true at the time
-      // of this implementation.
       if (type != GL_UNSIGNED_BYTE) {
-        LOCAL_SET_GL_ERROR(
-            GL_INVALID_OPERATION, "glReadPixels",
-            "unsupported readPixel format");
         return error::kNoError;
       }
       switch (format) {
         case GL_RGBA:
         case GL_BGRA_EXT:
         case GL_ALPHA: {
           int offset = (format == GL_ALPHA) ? 0 : 3;
           int step = (format == GL_ALPHA) ? 1 : 4;
           uint8* dst = static_cast<uint8*>(pixels) + offset;
           for (GLint yy = 0; yy < height; ++yy) {
@@ skipping 3491 matching lines @@
   return error::kNoError;
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu