Normalize top controls offset to (0, 1), Chromium-side.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index f4052f1fae136ba242f601b6ca310d48edde5bd6..fcdd81e14eb5ec4d344222999014f1a1647cd5c4 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -174,11 +174,14 @@ class CC_EXPORT LayerTreeHostImpl
   ScrollElasticityHelper* CreateScrollElasticityHelper() override;
 
   // TopControlsManagerClient implementation.
-  void SetControlsTopOffset(float offset) override;
-  float ControlsTopOffset() const override;
+  float TopControlsHeight() const override;
+  void SetCurrentTopControlsShownRatio(float offset) override;
+  float CurrentTopControlsShownRatio() const override;
   void DidChangeTopControlsPosition() override;
   bool HaveRootScrollLayer() const override;
 
+  void UpdateViewportContainerSizes();
+
   struct CC_EXPORT FrameData : public RenderPassSink {
     FrameData();
     ~FrameData() override;
@@ -530,7 +533,6 @@ class CC_EXPORT LayerTreeHostImpl
       gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
       int id);
 
-  void UpdateViewportContainerSizes();
 
   // Virtual for testing.
   virtual void AnimateLayers(base::TimeTicks monotonic_time);