Delay activation/draw on GPU tile work completion

cc/resources/resource_provider.cc

 // Copyright 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 "cc/resources/resource_provider.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 956 matching lines @@
         gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
         created_sync_token = true;
       }
 
       resource->UpdateSyncToken(sync_token);
       resource->SetSynchronized();
     }
   }
 }
 
+gpu::SyncToken ResourceProvider::GetSyncTokenForResources(
+    const ResourceIdArray& resource_ids) {
+  gpu::SyncToken latest_sync_token;
+  for (ResourceId id : resource_ids) {
+    const gpu::SyncToken& sync_token = GetResource(id)->mailbox().sync_token();
+    if (sync_token.release_count() > latest_sync_token.release_count())
+      latest_sync_token = sync_token;
+  }
+  return latest_sync_token;
+}
+
 ResourceProvider::Resource* ResourceProvider::InsertResource(
     ResourceId id,
     Resource resource) {
   std::pair<ResourceMap::iterator, bool> result =
       resources_.insert(ResourceMap::value_type(id, std::move(resource)));
   DCHECK(result.second);
   return &result.first->second;
 }
 
 ResourceProvider::Resource* ResourceProvider::GetResource(ResourceId id) {
@@ skipping 1164 matching lines @@
 
     const int kImportance = 2;
     pmd->CreateSharedGlobalAllocatorDump(guid);
     pmd->AddOwnershipEdge(dump->guid(), guid, kImportance);
   }
 
   return true;
 }
 
 }  // namespace cc