Implement EXT_draw_buffers WebGL extention support in command buffer.

gpu/command_buffer/common/gles2_cmd_utils.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 here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 #define GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 
@@ skipping 119 matching lines @@
 
   static uint32 GLErrorBitToGLError(uint32 error_bit);
 
   static uint32 IndexToGLFaceTarget(int index);
 
   // Returns a bitmask for the channels the given format supports.
   // See ChannelBits.
   static uint32 GetChannelsForFormat(int format);
 
   // Returns a bitmask for the channels the given attachment type needs.
-  static uint32 GetChannelsNeededForAttachmentType(int type);
+  static uint32 GetChannelsNeededForAttachmentType(
+      int type, uint32 max_color_attachments);
 
   static bool IsNPOT(uint32 value) {
     return value > 0 && (value & (value - 1)) != 0;
   }
 
   static std::string GetStringEnum(uint32 value);
   static std::string GetStringBool(uint32 value);
   static std::string GetStringError(uint32 value);
 
   // Parses a uniform name.
@@ skipping 39 matching lines @@
   bool buffer_preserved_;
   bool share_resources_;
   bool bind_generates_resource_;
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_