Adding momentum/overscroll to views:: ScrollViews

ui/views/controls/scroll_view.h

Index: ui/views/controls/scroll_view.h
diff --git a/ui/views/controls/scroll_view.h b/ui/views/controls/scroll_view.h
index da384801d9682208c19ae558986b06fdb3bbece9..28c9a12d8e69ac31d38450215f915f1bd0088ff6 100644
--- a/ui/views/controls/scroll_view.h
+++ b/ui/views/controls/scroll_view.h
@@ -12,7 +12,14 @@
 #include "base/macros.h"
 #include "ui/views/controls/scrollbar/scroll_bar.h"
 
+namespace gfx {
+class ScrollOffset;
+}
+
 namespace views {
+namespace test {
+class ScrollViewTestApi;
+}
 
 /////////////////////////////////////////////////////////////////////////////
 //
@@ -84,8 +91,10 @@ class VIEWS_EXPORT ScrollView : public View, public ScrollBarController {
   bool OnMouseWheel(const ui::MouseWheelEvent& e) override;
   void OnMouseEntered(const ui::MouseEvent& event) override;
   void OnMouseExited(const ui::MouseEvent& event) override;
+  void OnScrollEvent(ui::ScrollEvent* event) override;
   void OnGestureEvent(ui::GestureEvent* event) override;
   const char* GetClassName() const override;
+  ScrollView* EnclosingScrollView() override;
 
   // ScrollBarController overrides:
   void ScrollToPosition(ScrollBar* source, int position) override;
@@ -94,7 +103,7 @@ class VIEWS_EXPORT ScrollView : public View, public ScrollBarController {
                          bool is_positive) override;
 
  private:
-  FRIEND_TEST_ALL_PREFIXES(ScrollViewTest, CornerViewVisibility);
+  friend class test::ScrollViewTestApi;
   class Viewport;
 
   // Used internally by SetHeader() and SetContents() to reset the view.  Sets
@@ -121,9 +130,18 @@ class VIEWS_EXPORT ScrollView : public View, public ScrollBarController {
   // Update the scrollbars positions given viewport and content sizes.
   void UpdateScrollBarPositions();
 
-  // The current contents and its viewport. |contents_| is contained in
-  // |contents_viewport_|.
+  // Gets and sets the current scroll offset.
+  gfx::ScrollOffset CurrentOffset() const;
+  void ScrollToOffset(const gfx::ScrollOffset& offset);
+
+  // Callback entrypoint when hosted layers are scrolled by the compositor.
+  void OnLayerScrolled();
+
+  // The current contents and its viewport. |contents_| is contained in the
+  // layer-backed |contents_container_| which guarantees it is at least as high
+  // and wide as the |contents_viewport_|, which does the clipping.
   View* contents_;
+  View* contents_container_;
   View* contents_viewport_;
 
   // The current header and its viewport. |header_| is contained in