Add glReadPixel service implemenation....

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2006-2009 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.
 
 #include <vector>
 #include <string>
 #include <map>
 #include <build/build_config.h>
 #include "base/scoped_ptr.h"
 #define GLES2_GPU_SERVICE 1
@@ skipping 903 matching lines @@
     }
     glVertexAttribPointer(indx, size, type, normalized, stride, ptr);
   } else {
     SetGLError(GL_INVALID_VALUE);
   }
   return parse_error::kParseNoError;
 }
 
 parse_error::ParseError GLES2DecoderImpl::HandleReadPixels(
     uint32 immediate_data_size, const gles2::ReadPixels& c) {
-  // TODO(gman): Implement.
+  GLint x = c.x;
+  GLint y = c.y;
+  GLsizei width = c.width;
+  GLsizei height = c.height;
+  GLenum format = c.format;
+  GLenum type = c.type;
+  uint32 pixels_size = GLES2Util::ComputeImageDataSize(
+      width, height, format, type, pack_alignment_);
+  void* pixels = GetSharedMemoryAs<void*>(
+      c.pixels_shm_id, c.pixels_shm_offset, pixels_size);
+  parse_error::ParseError result = ValidateReadPixels(
+      this, immediate_data_size, x, y, width, height, format, type, pixels);
+  if (result != parse_error::kParseNoError) {
+    return result;
+  }
+  glReadPixels(x, y, width, height, format, type, pixels);
   return parse_error::kParseNoError;
 }
 
 parse_error::ParseError GLES2DecoderImpl::HandlePixelStorei(
     uint32 immediate_data_size, const gles2::PixelStorei& c) {
   GLenum pname = c.pname;
   GLenum param = c.param;
   parse_error::ParseError result =
     ValidatePixelStorei(this, immediate_data_size, pname, param);
   if (result != parse_error::kParseNoError) {
@@ skipping 292 matching lines @@
 }
 
 // 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 command_buffer