Pinch/Zoom Infrastructure & Plumbing CL

cc/layers/layer.h

 // Copyright 2010 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_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <set>
 #include <string>
 
@@ skipping 251 matching lines @@
     return draw_properties_.render_surface.get();
   }
   int num_unclipped_descendants() const {
     return draw_properties_.num_unclipped_descendants;
   }
 
   void SetScrollOffset(gfx::Vector2d scroll_offset);
   gfx::Vector2d scroll_offset() const { return scroll_offset_; }
   void SetScrollOffsetFromImplSide(gfx::Vector2d scroll_offset);
 
-  void SetMaxScrollOffset(gfx::Vector2d max_scroll_offset);
-  gfx::Vector2d max_scroll_offset() const { return max_scroll_offset_; }
+  gfx::Vector2d MaxScrollOffset() const;
 
-  void SetScrollable(bool scrollable);
-  bool scrollable() const { return scrollable_; }
+  void SetScrollClipLayer(Layer* clip_layer);
+  bool scrollable() const { return !!scroll_clip_layer_; }
 
   void SetUserScrollable(bool horizontal, bool vertical);
   bool user_scrollable_horizontal() const {
     return user_scrollable_horizontal_;
   }
   bool user_scrollable_vertical() const { return user_scrollable_vertical_; }
 
   void SetShouldScrollOnMainThread(bool should_scroll_on_main_thread);
   bool should_scroll_on_main_thread() const {
     return should_scroll_on_main_thread_;
@@ skipping 275 matching lines @@
   // This pointer value is nil when a Layer is not in a tree and is
   // updated via SetLayerTreeHost() if a layer moves between trees.
   LayerTreeHost* layer_tree_host_;
 
   scoped_refptr<LayerAnimationController> layer_animation_controller_;
 
   // Layer properties.
   gfx::Size bounds_;
 
   gfx::Vector2d scroll_offset_;
-  gfx::Vector2d max_scroll_offset_;
+  // This variable indicates which ancestor layer (if any) whose size,
+  // transformed relative to this layer, defines the maximum scroll offset for
+  // this layer.
+  Layer* scroll_clip_layer_;
   bool scrollable_ : 1;
   bool should_scroll_on_main_thread_ : 1;
   bool have_wheel_event_handlers_ : 1;
   bool user_scrollable_horizontal_ : 1;
   bool user_scrollable_vertical_ : 1;
   bool is_root_for_isolated_group_ : 1;
   bool is_container_for_fixed_position_layers_ : 1;
   bool is_drawable_ : 1;
   bool hide_layer_and_subtree_ : 1;
   bool masks_to_bounds_ : 1;
@@ skipping 38 matching lines @@
   DrawProperties<Layer> draw_properties_;
 
   PaintProperties paint_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_