Re-land: cc: Use worker context for one-copy tile initialization.

cc/output/output_surface.cc

 // Copyright (c) 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/output/output_surface.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 199 matching lines @@
 OverlayCandidateValidator* OutputSurface::GetOverlayCandidateValidator() const {
   return nullptr;
 }
 
 void OutputSurface::SetWorkerContextShouldAggressivelyFreeResources(
     bool aggressively_free_resources) {
   TRACE_EVENT1("cc",
                "OutputSurface::SetWorkerContextShouldAggressivelyFreeResources",
                "aggressively_free_resources", aggressively_free_resources);
   if (auto* context_provider = worker_context_provider()) {
-    // The context lock must be held while accessing the worker context.
-    base::AutoLock context_lock(*context_provider->GetLock());
-
-    // Allow context to bind to current thread.
-    context_provider->DetachFromThread();
+    ContextProvider::ScopedContextGL scoped_context(context_provider);
 
     if (aggressively_free_resources) {
       context_provider->DeleteCachedResources();
     }
 
     if (auto* context_support = context_provider->ContextSupport()) {
       context_support->SetAggressivelyFreeResources(
           aggressively_free_resources);
     }
-
-    // Allow context to bind to other threads.
-    context_provider->DetachFromThread();
   }
 }
 
 bool OutputSurface::SurfaceIsSuspendForRecycle() const {
   return false;
 }
 
 }  // namespace cc