cc: Remove ScheduleOnOriginThread() and CompleteOnOriginThread().

cc/tiles/tile_task_manager.h

Index: cc/tiles/tile_task_manager.h
diff --git a/cc/tiles/tile_task_manager.h b/cc/tiles/tile_task_manager.h
index e670b415602ad33e4e75111e982e5d843fcd7447..60294d6722d72a28562c082e7cbe2c6aa743d9a8 100644
--- a/cc/tiles/tile_task_manager.h
+++ b/cc/tiles/tile_task_manager.h
@@ -23,16 +23,14 @@ class CC_EXPORT TileTaskManager {
 
   // Schedule running of tile tasks in |graph| and all dependencies.
   // Previously scheduled tasks that are not in |graph| will be canceled unless
-  // already running. Once scheduled, reply callbacks are guaranteed to run for
-  // all tasks even if they later get canceled by another call to
-  // ScheduleTasks().
+  // already running. Once scheduled and if not canceled by next scheduling,
+  // tasks are guaranteed to run.
   virtual void ScheduleTasks(TaskGraph* graph) = 0;
 
-  // Check for completed tasks and dispatch reply callbacks.
+  // Check for completed tasks and call OnTaskCompleted() on them.
   virtual void CheckForCompletedTasks() = 0;
 
-  // Shutdown after canceling all previously scheduled tasks. Reply callbacks
-  // are still guaranteed to run when CheckForCompletedTasks() is called.
+  // Shutdown after canceling all previously scheduled tasks.
   virtual void Shutdown() = 0;
 
   // Get RasterBufferProvider.
@@ -61,7 +59,6 @@ class CC_EXPORT TileTaskManagerImpl : public TileTaskManager {
   std::unique_ptr<RasterBufferProvider> raster_buffer_provider_;
   TaskGraphRunner* task_graph_runner_;
   const NamespaceToken namespace_token_;
-  Task::Vector completed_tasks_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TileTaskManagerImpl);