[#4] Pass gfx structs by const ref (gfx::PointF)

cc/trees/layer_tree_host_impl.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <list>
 #include <set>
 #include <string>
@@ skipping 452 matching lines @@
   void ReleaseTreeResources();
   void EnforceZeroBudget(bool zero_budget);
 
   void AnimatePageScale(base::TimeTicks monotonic_time);
   void AnimateScrollbars(base::TimeTicks monotonic_time);
   void AnimateTopControls(base::TimeTicks monotonic_time);
 
   gfx::Vector2dF ScrollLayerWithViewportSpaceDelta(
       LayerImpl* layer_impl,
       float scale_from_viewport_to_screen_space,
-      gfx::PointF viewport_point,
+      const gfx::PointF& viewport_point,
       gfx::Vector2dF viewport_delta);
 
   void UpdateMaxScrollOffset();
   void TrackDamageForAllSurfaces(
       LayerImpl* root_draw_layer,
       const LayerImplList& render_surface_layer_list);
 
   void UpdateTileManagerMemoryPolicy(const ManagedMemoryPolicy& policy);
 
   // Returns false if the frame should not be displayed. This function should
   // only be called from PrepareToDraw, as DidDrawAllLayers must be called
   // if this helper function is called.
   bool CalculateRenderPasses(FrameData* frame);
 
   void SendReleaseResourcesRecursive(LayerImpl* current);
   bool EnsureRenderSurfaceLayerList();
   void ClearCurrentlyScrollingLayer();
 
   bool HandleMouseOverScrollbar(LayerImpl* layer_impl,
-                                gfx::PointF device_viewport_point);
+                                const gfx::PointF& device_viewport_point);
 
   void AnimateScrollbarsRecursive(LayerImpl* layer,
                                   base::TimeTicks time);
 
   void UpdateCurrentFrameTime(base::TimeTicks* ticks, base::Time* now) const;
 
   LayerImpl* FindScrollLayerForDeviceViewportPoint(
-      gfx::PointF device_viewport_point,
+      const gfx::PointF& device_viewport_point,
       InputHandler::ScrollInputType type,
       LayerImpl* layer_hit_by_point,
       bool* scroll_on_main_thread) const;
-  float DeviceSpaceDistanceToLayer(gfx::PointF device_viewport_point,
+  float DeviceSpaceDistanceToLayer(const gfx::PointF& device_viewport_point,
                                    LayerImpl* layer_impl);
   void StartScrollbarAnimationRecursive(LayerImpl* layer, base::TimeTicks time);
   void SetManagedMemoryPolicy(const ManagedMemoryPolicy& policy,
                               bool zero_budget);
   void EnforceManagedMemoryPolicy(const ManagedMemoryPolicy& policy);
 
   void DidInitializeVisibleTile();
 
   void MarkUIResourceNotEvicted(UIResourceId uid);
 
@@ skipping 135 matching lines @@
   int id_;
 
   std::set<SwapPromiseMonitor*> swap_promise_monitor_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_