Update from https://crrev.com/317530

cc/resources/one_copy_tile_task_worker_pool.cc

 // Copyright 2014 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/one_copy_tile_task_worker_pool.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/strings/stringprintf.h"
@@ skipping 149 matching lines @@
   }
 
   TaskGraph empty;
   task_graph_runner_->ScheduleTasks(namespace_token_, &empty);
   task_graph_runner_->WaitForTasksToFinishRunning(namespace_token_);
 }
 
 void OneCopyTileTaskWorkerPool::ScheduleTasks(TileTaskQueue* queue) {
   TRACE_EVENT0("cc", "OneCopyTileTaskWorkerPool::ScheduleTasks");
 
+#if DCHECK_IS_ON()
+  {
+    base::AutoLock lock(lock_);
+    DCHECK(!shutdown_);
+  }
+#endif
+
   if (tasks_pending_.none())
     TRACE_EVENT_ASYNC_BEGIN0("cc", "ScheduledTasks", this);
 
   // Mark all task sets as pending.
   tasks_pending_.set();
 
   unsigned priority = kTileTaskPriorityBase;
 
   graph_.Reset();
 
@@ skipping 311 matching lines @@
                             resource_pool_->total_memory_usage_bytes());
   staging_state->SetInteger("pending_copy_count",
                             resource_pool_->total_resource_count() -
                                 resource_pool_->acquired_resource_count());
   staging_state->SetInteger("bytes_pending_copy",
                             resource_pool_->total_memory_usage_bytes() -
                                 resource_pool_->acquired_memory_usage_bytes());
 }
 
 }  // namespace cc