Remove unnecessary sync token on CopyPlaneTexture returned Resource.

cc/resources/video_resource_updater.cc

 // Copyright 2013 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 "cc/resources/video_resource_updater.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 620 matching lines @@
 
   gl->WaitSyncTokenCHROMIUM(mailbox_holder.sync_token.GetConstData());
   uint32_t src_texture_id = gl->CreateAndConsumeTextureCHROMIUM(
       mailbox_holder.texture_target, mailbox_holder.mailbox.name);
   gl->CopySubTextureCHROMIUM(src_texture_id, lock.texture_id(), 0, 0, 0, 0,
                              output_plane_resource_size.width(),
                              output_plane_resource_size.height(), false, false,
                              false);
   gl->DeleteTextures(1, &src_texture_id);
 
-  // Sync point for use of frame copy.
-  gpu::SyncToken sync_token;
-  const uint64_t fence_sync = gl->InsertFenceSyncCHROMIUM();
-  gl->ShallowFlushCHROMIUM();
-  gl->GenSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
-
   // Done with the source video frame texture at this point.
   video_frame->UpdateReleaseSyncToken(&client);
 
-  TextureMailbox mailbox(resource->mailbox(), sync_token, GL_TEXTURE_2D,
+  // VideoResourceUpdater shares a context with the compositor so a
+  // sync token is not required.
+  TextureMailbox mailbox(resource->mailbox(), gpu::SyncToken(), GL_TEXTURE_2D,
                          video_frame->coded_size(), false, false);
   mailbox.set_color_space(video_frame->ColorSpace());
   external_resources->mailboxes.push_back(mailbox);
 
   external_resources->release_callbacks.push_back(
       base::Bind(&RecycleResource, AsWeakPtr(), resource->resource_id()));
 }
 
 VideoFrameExternalResources VideoResourceUpdater::CreateForHardwarePlanes(
     scoped_refptr<media::VideoFrame> video_frame) {
@@ skipping 68 matching lines @@
   if (lost_resource) {
     resource_it->clear_refs();
     updater->DeleteResource(resource_it);
     return;
   }
 
   resource_it->remove_ref();
 }
 
 }  // namespace cc