Pinch/Zoom Infrastructure & Plumbing CL

cc/layers/painted_scrollbar_layer.h

 // Copyright 2013 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_LAYERS_PAINTED_SCROLLBAR_LAYER_H_
 #define CC_LAYERS_PAINTED_SCROLLBAR_LAYER_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/input/scrollbar.h"
 #include "cc/layers/contents_scaling_layer.h"
 #include "cc/layers/scrollbar_layer_interface.h"
 #include "cc/layers/scrollbar_theme_painter.h"
 #include "cc/resources/layer_updater.h"
 #include "cc/resources/scoped_ui_resource.h"
 
 namespace cc {
 class ScrollbarThemeComposite;
 
 class CC_EXPORT PaintedScrollbarLayer : public ScrollbarLayerInterface,
                                         public ContentsScalingLayer {
  public:
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE;
 
   static scoped_refptr<PaintedScrollbarLayer> Create(
       scoped_ptr<Scrollbar> scrollbar,
-      int scroll_layer_id);
+      Layer* scroll_layer);
 
   virtual bool OpacityCanAnimateOnImplThread() const OVERRIDE;
   virtual ScrollbarLayerInterface* ToScrollbarLayer() OVERRIDE;
 
   // ScrollbarLayerInterface
   virtual int ScrollLayerId() const OVERRIDE;
-  virtual void SetScrollLayerId(int id) OVERRIDE;
+  virtual void SetScrollLayer(scoped_refptr<Layer> layer) OVERRIDE;
+  virtual void SetClipLayer(scoped_refptr<Layer> layer) OVERRIDE;
 
   virtual ScrollbarOrientation orientation() const OVERRIDE;
 
   // Layer interface
   virtual bool Update(ResourceUpdateQueue* queue,
                       const OcclusionTracker* occlusion) OVERRIDE;
   virtual void SetLayerTreeHost(LayerTreeHost* host) OVERRIDE;
   virtual void PushPropertiesTo(LayerImpl* layer) OVERRIDE;
+  virtual void PushScrollClipPropertiesTo(LayerImpl* layer) OVERRIDE;
   virtual void CalculateContentsScale(float ideal_contents_scale,
                                       float device_scale_factor,
                                       float page_scale_factor,
                                       bool animating_transform_to_screen,
                                       float* contents_scale_x,
                                       float* contents_scale_y,
                                       gfx::Size* content_bounds) OVERRIDE;
 
  protected:
-  PaintedScrollbarLayer(scoped_ptr<Scrollbar> scrollbar, int scroll_layer_id);
+  PaintedScrollbarLayer(scoped_ptr<Scrollbar> scrollbar, Layer* scroll_layer);
   virtual ~PaintedScrollbarLayer();
 
   // For unit tests
   UIResourceId track_resource_id() {
     return track_resource_.get() ? track_resource_->id() : 0;
   }
   UIResourceId thumb_resource_id() {
     return thumb_resource_.get() ? thumb_resource_->id() : 0;
   }
   void UpdateThumbAndTrackGeometry();
 
  private:
   gfx::Rect ScrollbarLayerRectToContentRect(const gfx::Rect& layer_rect) const;
   gfx::Rect OriginThumbRect() const;
 
   template<typename T> void UpdateProperty(T value, T* prop) {
     if (*prop == value)
       return;
     *prop = value;
     SetNeedsPushProperties();
   }
 
   int MaxTextureSize();
   float ClampScaleToMaxTextureSize(float scale);
 
   UIResourceBitmap RasterizeScrollbarPart(const gfx::Rect& rect,
                                           ScrollbarPart part);
 
   scoped_ptr<Scrollbar> scrollbar_;
-  int scroll_layer_id_;
+  scoped_refptr<Layer> scroll_layer_;

[aelias_OOO_until_Jul13, 2014/01/16 03:44:04]

Can this be a weak pointer instead?  Refptrs risk the danger of layer trees
inappropriately remaining alive and wasting memory.

Also, can't you use the one from ScrollbarLayerImplBase instead of tracking it
separately?

[wjmaclean, 2014/01/16 15:07:32]

I will investigate, and re-use the one in ScrollbarLayerImplBase assuming all
else is equal.

+  scoped_refptr<Layer> clip_layer_;
 
   // Snapshot of properties taken in UpdateThumbAndTrackGeometry and used in
   // PushPropertiesTo.
   int thumb_thickness_;
   int thumb_length_;
   gfx::Point location_;
   gfx::Rect track_rect_;
   bool is_overlay_;
   bool has_thumb_;
 
   scoped_ptr<ScopedUIResource> track_resource_;
   scoped_ptr<ScopedUIResource> thumb_resource_;
 
   DISALLOW_COPY_AND_ASSIGN(PaintedScrollbarLayer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PAINTED_SCROLLBAR_LAYER_H_