cc/blimp: Add synchronization for scroll/scale state.

cc/trees/layer_tree.h

Index: cc/trees/layer_tree.h
diff --git a/cc/trees/layer_tree.h b/cc/trees/layer_tree.h
index 9f749bfe0770d6c3537f1d87033cce08f44f00df..78bb2ecfe956082f460e16f1ce222a23a1dcce22 100644
--- a/cc/trees/layer_tree.h
+++ b/cc/trees/layer_tree.h
@@ -102,6 +102,8 @@ class CC_EXPORT LayerTree : public MutatorHostClient {
                                    float min_page_scale_factor,
                                    float max_page_scale_factor);
   float page_scale_factor() const { return inputs_.page_scale_factor; }
+  float min_page_scale_factor() const { return inputs_.min_page_scale_factor; }
+  float max_page_scale_factor() const { return inputs_.max_page_scale_factor; }
 
   void set_background_color(SkColor color) { inputs_.background_color = color; }
   SkColor background_color() const { return inputs_.background_color; }
@@ -181,7 +183,8 @@ class CC_EXPORT LayerTree : public MutatorHostClient {
 
   void SetPropertyTreesNeedRebuild();
 
-  void PushPropertiesTo(LayerTreeImpl* tree_impl);
+  void PushPropertiesTo(LayerTreeImpl* tree_impl,
+                        float unapplied_page_scale_delta);
 
   void ToProtobuf(proto::LayerTree* proto, bool inputs_only);
   void FromProtobuf(const proto::LayerTree& proto);