cc: Remove ScheduleOnOriginThread() and CompleteOnOriginThread().

cc/raster/task_graph_runner.h

Index: cc/raster/task_graph_runner.h
diff --git a/cc/raster/task_graph_runner.h b/cc/raster/task_graph_runner.h
index d5f8ceecb1935e340135fb05f1d775e074129eb1..8aa0d8999059a9dba7bc2716448c32a539aca1ea 100644
--- a/cc/raster/task_graph_runner.h
+++ b/cc/raster/task_graph_runner.h
@@ -21,6 +21,9 @@ namespace cc {
 
 class TaskGraphRunner;
 
+typedef uint32_t TaskTypeId;
+const TaskTypeId kDefaultTaskTypeId = 0;
+
 // A task which can be run by a TaskGraphRunner. To run a Task, it should be
 // inserted into a TaskGraph, which can then be scheduled on the
 // TaskGraphRunner.
@@ -28,6 +31,8 @@ class CC_EXPORT Task : public base::RefCountedThreadSafe<Task> {
  public:
   typedef std::vector<scoped_refptr<Task>> Vector;
 
+  TaskTypeId GetTaskTypeId();

[prashant.n, 2016/04/11 14:17:48]

This looks little wierd. But I don't see any other approach. Pls. comment on
this if this is not okay?

Basically what CompleteOnOriginThread was doing is job of Task owner (viz.
TileManager, [Software|Gpu]ImageDecodeController). So we need to move those out
of Task interfaces making Task leaner.

+
   // Subclasses should implement this method. RunOnWorkerThread may be called
   // on any thread, and subclasses are responsible for locking and thread
   // safety.
@@ -40,9 +45,12 @@ class CC_EXPORT Task : public base::RefCountedThreadSafe<Task> {
  protected:
   friend class base::RefCountedThreadSafe<Task>;
 
+  void SetTaskTypeId(TaskTypeId type_id);
+
   Task();
   virtual ~Task();
 
+  TaskTypeId type_id_;
   bool will_run_;
   bool did_run_;
 };