Move TaskGraph creation to TileManager

cc/tiles/tile_manager.h

Index: cc/tiles/tile_manager.h
diff --git a/cc/tiles/tile_manager.h b/cc/tiles/tile_manager.h
index abffc7cb5998794580de7a4956646a0ea6e40ff3..e9ca50867a3e03a03ed12ffe80cf39410885ed9b 100644
--- a/cc/tiles/tile_manager.h
+++ b/cc/tiles/tile_manager.h
@@ -86,11 +86,19 @@ struct RasterTaskCompletionStats {
 scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 RasterTaskCompletionStatsAsValue(const RasterTaskCompletionStats& stats);
 
+// kNumberOfTaskSets must be greater or equal to the number of values in
+// TileManager::NamedTaskSet.
+// TODO(reveman): Use template specialization to make it easy for client code to
+// check at compile time that the number of supported task sets is correct.
+static const size_t kNumberOfTaskSets = 3;
+using TaskSet = size_t;
+using TaskSetCollection = std::bitset<kNumberOfTaskSets>;

[reveman, 2015/11/26 00:18:30]

Can we get rid of all this and just build the correct task graph based on
Tile::required_for_activation() etc directly.

[ericrk, 2015/11/30 23:52:16]

this is more used for tracking which task sets are completed across all tasks
for firing callbacks, not really in construction. We can simplify this a bit
though (combine with the NamedTaskSet below).

[reveman, 2015/12/02 05:22:54]

I'm thinking that we just get rid of all this task set stuff now that that's no
longer forced on us as a result of living behind the TileTaskRunner interface
that is unaware of concepts such as activation, etc.

For example to keep track of what tasks have finished running we'd just use 3
bools:

bool tasks_required_for_activation_pending_;
bool tasks_required_for_draw_pending_;
bool tasks_pending_;

I think this would make for code that is much easier to understand and it
matches the interface exposed by the Tile class. e.g. there's a
Tile::required_for_activation() getter and not a Tile::task_sets() getter.

+
 // This class manages tiles, deciding which should get rasterized and which
 // should no longer have any memory assigned to them. Tile objects are "owned"
 // by layers; they automatically register with the manager when they are
 // created, and unregister from the manager when they are deleted.
-class CC_EXPORT TileManager : public TileTaskRunnerClient {
+class CC_EXPORT TileManager {
  public:
   enum NamedTaskSet {
     REQUIRED_FOR_ACTIVATION,
@@ -109,7 +117,7 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
                                         base::SequencedTaskRunner* task_runner,
                                         size_t scheduled_raster_task_limit,
                                         bool use_partial_raster);
-  ~TileManager() override;
+  virtual ~TileManager();
 
   // Assigns tile memory and schedules work to prepare tiles for drawing.
   // - Runs client_->NotifyReadyToActivate() when all tiles required for
@@ -217,9 +225,6 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
   virtual void Release(Tile* tile);
   Tile::Id GetUniqueTileId() { return ++next_tile_id_; }
 
-  // Overriden from TileTaskRunnerClient:
-  void DidFinishRunningTileTasks(TaskSet task_set) override;
-
   typedef std::vector<PrioritizedTile> PrioritizedTileVector;
   typedef std::set<Tile*> TileSet;
 
@@ -288,6 +293,16 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
   ResourceFormat DetermineResourceFormat(const Tile* tile) const;
   bool DetermineResourceRequiresSwizzle(const Tile* tile) const;
 
+  void DidFinishRunningTileTasks(TaskSet task_set);
+
+  void BuildTaskGraph(
+      const PrioritizedTileVector& tiles_that_need_to_be_rasterized,
+      TaskGraph* graph,
+      scoped_refptr<TileTask>(&new_task_set_finished_tasks)[kNumberOfTaskSets]);
+
+  scoped_refptr<base::trace_event::ConvertableToTraceFormat>
+  ScheduledTasksStateAsValue() const;
+
   TileManagerClient* client_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   ResourcePool* resource_pool_;
@@ -311,10 +326,8 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
 
   std::vector<Tile*> released_tiles_;
 
-  // Queue used when scheduling raster tasks.
-  TileTaskQueue raster_queue_;
-
-  std::vector<scoped_refptr<RasterTask>> orphan_raster_tasks_;
+  std::vector<scoped_refptr<TileTask>> orphan_tasks_;
+  TaskSetCollection tasks_pending_;
 
   UniqueNotifier more_tiles_need_prepare_check_notifier_;
 
@@ -338,6 +351,8 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
   uint64_t prepare_tiles_count_;
   uint64_t next_tile_id_;
 
+  base::WeakPtrFactory<TileManager> task_set_finished_weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(TileManager);
 };