CC: Add a scheduled action for ManageTiles

cc/scheduler/scheduler_state_machine.h

Index: cc/scheduler/scheduler_state_machine.h
diff --git a/cc/scheduler/scheduler_state_machine.h b/cc/scheduler/scheduler_state_machine.h
index aaefa37bc67bad6c2634d8b62a3c44bd59a64c57..c280dbf2d0b9426d52ea688faa168d21d977d1d4 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -100,6 +100,7 @@ class CC_EXPORT SchedulerStateMachine {
     ACTION_DRAW_AND_READBACK,
     ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
     ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD,
+    ACTION_MANAGE_TILES,
   };
   static const char* ActionToString(Action action);
 
@@ -128,6 +129,10 @@ class CC_EXPORT SchedulerStateMachine {
   // or the screen being damaged and simply needing redisplay.
   void SetNeedsRedraw();
 
+  // Indicates that manage-tiles is required. This guarantees another
+  // ManageTiles will occur shortly (even if no redraw is required).
+  void SetNeedsManageTiles();
+
   // Indicates whether a redraw is required because we are currently rendering
   // with a low resolution or checkerboarded tile.
   void SetSwapUsedIncompleteTile(bool used_incomplete_tile);
@@ -197,6 +202,7 @@ class CC_EXPORT SchedulerStateMachine {
   bool ShouldUpdateVisibleTiles() const;
   bool ShouldSendBeginFrameToMainThread() const;
   bool ShouldCommit() const;
+  bool ShouldManageTiles() const;
 
   bool HasDrawnAndSwappedThisFrame() const;
   bool HasActivatedPendingTreeThisFrame() const;
@@ -206,6 +212,7 @@ class CC_EXPORT SchedulerStateMachine {
   void UpdateStateOnCommit(bool commit_was_aborted);
   void UpdateStateOnActivation();
   void UpdateStateOnDraw(bool did_swap);
+  void UpdateStateOnManageTiles();
 
   const SchedulerSettings settings_;
 
@@ -222,6 +229,7 @@ class CC_EXPORT SchedulerStateMachine {
   int last_frame_number_where_update_visible_tiles_was_called_;
   int consecutive_failed_draws_;
   bool needs_redraw_;
+  bool needs_manage_tiles_;
   bool swap_used_incomplete_tile_;
   bool needs_commit_;
   bool main_thread_needs_layer_textures_;