SetNeedsRedraw directly when updating a visible tile.

cc/resources/tile_manager.h

Index: cc/resources/tile_manager.h
diff --git a/cc/resources/tile_manager.h b/cc/resources/tile_manager.h
index f5bea383141a38c325f695ed2247e9b7561331a9..1eba480213b85b106eff5ddbd9d6e5f766211379 100644
--- a/cc/resources/tile_manager.h
+++ b/cc/resources/tile_manager.h
@@ -60,6 +60,12 @@ class CC_EXPORT TileManagerClient {
   virtual void BuildRasterQueue(RasterTilePriorityQueue* queue,
                                 TreePriority tree_priority) = 0;
 
+  // Called when all tiles from the previous BuildRasterQueue have been
+  // processed. Each BuildRasterQueue call is followed by either another
+  // BuildRasterQueue call (when some tiles were processed but not all), or a
+  // FinishedRasterQueue() call.
+  virtual void FinishedRasterQueue() = 0;

[reveman, 2014/10/31 16:08:50]

If we're adding another notification then we should make it consistent with
NotifyReadyToActivate(), hence something like NotifyAllTilesReadyToDraw(). I
don't think we need this though. Manfred's ReadyToDraw notification is really
what we want here: https://codereview.chromium.org/672283003/

Can we either rebase this on that or just reset
LTHI::active_visible_tile_is_top_of_raster_queue_ when being notified that some
visible tile as been initialized and improve it after landing Manfred's patch?

[danakj, 2014/10/31 16:34:39]

Without this callback my pinch zoom test fails to make forward progress because
there's nothing to call UpdateVisibleTiles, so theres nothing to call
NotifyTileStateChange in the case where DidFinishRunningTasks early outs.

+
   // Given an empty eviction tile priority queue, this will build a priority
   // queue that will return tiles in order in which they should be evicted.
   // Note if the queue was previous built, Reset must be called on it.
@@ -104,8 +110,7 @@ class CC_EXPORT TileManager : public RasterizerClient,
 
   void ManageTiles(const GlobalStateThatImpactsTilePriority& state);
 
-  // Returns true when visible tiles have been initialized.
-  bool UpdateVisibleTiles();
+  void UpdateVisibleTiles();
 
   scoped_refptr<Tile> CreateTile(RasterSource* raster_source,
                                  const gfx::Size& tile_size,
@@ -248,7 +253,6 @@ class CC_EXPORT TileManager : public RasterizerClient,
 
   RenderingStatsInstrumentation* rendering_stats_instrumentation_;
 
-  bool did_initialize_visible_tile_;
   bool did_check_for_completed_tasks_since_last_schedule_tasks_;
   bool did_oom_on_last_assign_;