Implement EXT_draw_buffers WebGL extention support in command buffer.

gpu/command_buffer/client/gles2_cmd_helper_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!
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_GLES2_CMD_HELPER_AUTOGEN_H_
 #define GPU_COMMAND_BUFFER_CLIENT_GLES2_CMD_HELPER_AUTOGEN_H_
@@ skipping 2062 matching lines @@
   }
 
   void WaitSyncPointCHROMIUM(GLuint sync_point) {
     gles2::cmds::WaitSyncPointCHROMIUM* c =
         GetCmdSpace<gles2::cmds::WaitSyncPointCHROMIUM>();
     if (c) {
       c->Init(sync_point);
     }
   }
 
+  void DrawBuffersEXT(
+      GLsizei count, uint32 bufs_shm_id, uint32 bufs_shm_offset) {
+    gles2::cmds::DrawBuffersEXT* c =
+        GetCmdSpace<gles2::cmds::DrawBuffersEXT>();
+    if (c) {
+      c->Init(count, bufs_shm_id, bufs_shm_offset);
+    }
+  }
+
+  void DrawBuffersEXTImmediate(GLsizei count, const GLenum* bufs) {
+    const uint32 size =
+        gles2::cmds::DrawBuffersEXTImmediate::ComputeSize(count);
+    gles2::cmds::DrawBuffersEXTImmediate* c =
+        GetImmediateCmdSpaceTotalSize<gles2::cmds::DrawBuffersEXTImmediate>(
+            size);
+    if (c) {
+      c->Init(count, bufs);
+    }
+  }
+
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_CMD_HELPER_AUTOGEN_H_