Made Blink aware of top controls offset (Chromium-side)

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index e21b1c87435452ca3bf8bfc05cb60854613e0314..ca0580f40312d1fb157715c9dc8da406cee1fb2d 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -291,6 +291,29 @@ class CC_EXPORT LayerTreeImpl {
   void RegisterPictureLayerImpl(PictureLayerImpl* layer);
   void UnregisterPictureLayerImpl(PictureLayerImpl* layer);
 
+  void set_top_controls_content_offset(float offset) {
+    top_controls_content_offset_ = offset;
+  }
+  void set_top_controls_delta(float delta) {
+    top_controls_delta_ = delta;
+  }
+  void set_sent_top_controls_delta(float sent_delta) {
+    sent_top_controls_delta_ = sent_delta;
+  }
+
+  float top_controls_content_offset() const {
+    return top_controls_content_offset_;
+  }
+  float top_controls_delta() const {
+    return top_controls_delta_;
+  }
+  float sent_top_controls_delta() const {
+    return sent_top_controls_delta_;
+  }
+  float total_top_controls_content_offset() const {
+    return top_controls_content_offset_ + top_controls_delta_;
+  }
+
  protected:
   explicit LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl);
   void ReleaseResourcesRecursive(LayerImpl* current);
@@ -351,6 +374,11 @@ class CC_EXPORT LayerTreeImpl {
 
   int render_surface_layer_list_id_;
 
+  // Height of the top controls as known by Blink.
+  float top_controls_content_offset_;
+  float top_controls_delta_;
+  float sent_top_controls_delta_;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };