Revert of Added an extra sync token field for extra command buffer identification.

ppapi/proxy/ppapi_command_buffer_proxy.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 "ppapi/proxy/ppapi_command_buffer_proxy.h"
 
 #include "base/numerics/safe_conversions.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "ppapi/shared_impl/host_resource.h"
@@ skipping 195 matching lines @@
 void PpapiCommandBufferProxy::SignalSyncToken(const gpu::SyncToken& sync_token,
                                               const base::Closure& callback) {
   NOTIMPLEMENTED();
 }
 
 bool PpapiCommandBufferProxy::CanWaitUnverifiedSyncToken(
     const gpu::SyncToken* sync_token) {
   return false;
 }
 
-int32_t PpapiCommandBufferProxy::GetExtraCommandBufferData() const {
-  return 0;
-}
-
 uint32 PpapiCommandBufferProxy::InsertSyncPoint() {
   uint32 sync_point = 0;
   if (last_state_.error == gpu::error::kNoError) {
     Send(new PpapiHostMsg_PPBGraphics3D_InsertSyncPoint(
          ppapi::API_ID_PPB_GRAPHICS_3D, resource_, &sync_point));
   }
   return sync_point;
 }
 
 uint32 PpapiCommandBufferProxy::InsertFutureSyncPoint() {
@@ skipping 102 matching lines @@
   message->set_unblock(true);
   Send(message);
 
   flush_info_->flush_pending = false;
   flush_info_->resource.SetHostResource(0, 0);
   flushed_fence_sync_release_ = pending_fence_sync_release_;
 }
 
 }  // namespace proxy
 }  // namespace ppapi