cc: Split tiling set raster queues into all and required.

cc/resources/raster_tile_priority_queue.h

Index: cc/resources/raster_tile_priority_queue.h
diff --git a/cc/resources/raster_tile_priority_queue.h b/cc/resources/raster_tile_priority_queue.h
index 416a57a670a006e03daeaf7977d8d827b454f724..875b393fe7af599c723226ce66d1b0f6286a3c44 100644
--- a/cc/resources/raster_tile_priority_queue.h
+++ b/cc/resources/raster_tile_priority_queue.h
@@ -16,12 +16,19 @@
 
 namespace cc {
 
+// TODO(vmpstr): Consider virtualizing this and adding ::Create with the
+// parameters of ::Build that would create a simpler queue for required only
+// tiles (ie, there's no need for the heap if all we're interested in are the
+// required tiles.
 class CC_EXPORT RasterTilePriorityQueue {
  public:
+  enum class Type { ALL, REQUIRED_FOR_ACTIVATION, REQUIRED_FOR_DRAW };
+
   struct PairedTilingSetQueue {
     PairedTilingSetQueue();
     PairedTilingSetQueue(const PictureLayerImpl::Pair& layer_pair,
-                         TreePriority tree_priority);
+                         TreePriority tree_priority,
+                         Type type);
     ~PairedTilingSetQueue();
 
     bool IsEmpty() const;
@@ -45,7 +52,8 @@ class CC_EXPORT RasterTilePriorityQueue {
   ~RasterTilePriorityQueue();
 
   void Build(const std::vector<PictureLayerImpl::Pair>& paired_layers,
-             TreePriority tree_priority);
+             TreePriority tree_priority,
+             Type type);
   void Reset();
 
   bool IsEmpty() const;