Perform glReadPixels with PBOs in the gpu, if PBOs are available.

gpu/command_buffer/common/gles2_cmd_format_test_autogen.h

 // 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.
 
 // This file is auto-generated from
 // gpu/command_buffer/build_gles2_cmd_buffer.py
 // DO NOT EDIT!
 
 // This file contains unit tests for gles2 commmands
 // It is included by gles2_cmd_format_test.cc
@@ skipping 1785 matching lines @@
       &cmd,
       static_cast<GLint>(11),
       static_cast<GLint>(12),
       static_cast<GLsizei>(13),
       static_cast<GLsizei>(14),
       static_cast<GLenum>(15),
       static_cast<GLenum>(16),
       static_cast<uint32>(17),
       static_cast<uint32>(18),
       static_cast<uint32>(19),
-      static_cast<uint32>(20));
+      static_cast<uint32>(20),
+      static_cast<GLboolean>(21));
   EXPECT_EQ(static_cast<uint32>(cmds::ReadPixels::kCmdId),
             cmd.header.command);
   EXPECT_EQ(sizeof(cmd), cmd.header.size * 4u);
   EXPECT_EQ(static_cast<GLint>(11), cmd.x);
   EXPECT_EQ(static_cast<GLint>(12), cmd.y);
   EXPECT_EQ(static_cast<GLsizei>(13), cmd.width);
   EXPECT_EQ(static_cast<GLsizei>(14), cmd.height);
   EXPECT_EQ(static_cast<GLenum>(15), cmd.format);
   EXPECT_EQ(static_cast<GLenum>(16), cmd.type);
   EXPECT_EQ(static_cast<uint32>(17), cmd.pixels_shm_id);
   EXPECT_EQ(static_cast<uint32>(18), cmd.pixels_shm_offset);
   EXPECT_EQ(static_cast<uint32>(19), cmd.result_shm_id);
   EXPECT_EQ(static_cast<uint32>(20), cmd.result_shm_offset);
+  EXPECT_EQ(static_cast<GLboolean>(21), cmd.async);
   CheckBytesWrittenMatchesExpectedSize(
       next_cmd, sizeof(cmd));
 }
 
 TEST_F(GLES2FormatTest, ReleaseShaderCompiler) {
   cmds::ReleaseShaderCompiler& cmd =
       *GetBufferAs<cmds::ReleaseShaderCompiler>();
   void* next_cmd = cmd.Set(
       &cmd);
   EXPECT_EQ(static_cast<uint32>(cmds::ReleaseShaderCompiler::kCmdId),
@@ skipping 2667 matching lines @@
   EXPECT_EQ(kExpectedCmdSize, cmd.header.size * 4u);
   EXPECT_EQ(static_cast<GLsizei>(1), cmd.count);
   CheckBytesWrittenMatchesExpectedSize(
       next_cmd, sizeof(cmd) +
       RoundSizeToMultipleOfEntries(sizeof(data)));
   // TODO(gman): Check that data was inserted;
 }
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_FORMAT_TEST_AUTOGEN_H_