Check if priority actually changed in Tile::SetPriority()

cc/resources/tile.cc

Index: cc/resources/tile.cc
diff --git a/cc/resources/tile.cc b/cc/resources/tile.cc
index 48f3ae78ebd0600d04ab0f8ecce7d03f9389768d..20e862d705269a04cd25791e4bef08aad4522019 100644
--- a/cc/resources/tile.cc
+++ b/cc/resources/tile.cc
@@ -46,8 +46,10 @@ scoped_ptr<base::Value> Tile::AsValue() const {
 }
 
 void Tile::SetPriority(WhichTree tree, const TilePriority& priority) {
-  tile_manager_->WillModifyTilePriority(this, tree, priority);
-  priority_[tree] = priority;
+  if (priority_[tree] != priority) {

[enne (OOO), 2013/03/20 17:05:57]

style nit: early out return here instead.

[Xianzhu, 2013/03/20 17:24:45]

Done.

+    tile_manager_->WillModifyTilePriority(this, tree, priority);
+    priority_[tree] = priority;
+  }
 }
 
 }  // namespace cc