Wire ScrollEvent to views and handle it in app list.

- Pass ScrollEvent to views system;
  - Add a OnScrollEvent to View;
  - Forward ScrollEvent to RootView in Widget;
  - RootView dispatches ScrollEvent to view under where event happens
    and if not processed, pass it to the parent;
- Handle ScrollEvent to switch pages in app list;

BUG=131075
TEST=Verify two-finger scroll on touch pad switches pages in app list;

Review URL: https://chromiumcodereview.appspot.com/10577045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@143531 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 13 insertions, 0 deletions

diff --git a/ui/views/widget/root_view.cc b/ui/views/widget/root_view.cc
index 515fa23..5d2aba3 100644
--- a/ui/views/widget/root_view.cc
+++ b/ui/views/widget/root_view.cc
@@ -381,6 +381,15 @@ bool RootView::OnMouseWheel(const MouseWheelEvent& event) {
   return consumed;
 }
 
+bool RootView::OnScrollEvent(const ScrollEvent& event) {
+  ScrollEvent e(event, this);
+  bool consumed = false;
+  for (View* v = GetEventHandlerForPoint(e.location());
+       v && v != this && !consumed; v = v->parent())
+    consumed = v->OnScrollEvent(e);
+  return consumed;
+}
+
 ui::TouchStatus RootView::OnTouchEvent(const TouchEvent& event) {
   // TODO: this looks all wrong. On a TOUCH_PRESSED we should figure out the
   // view and target that view with all touches with the same id until the
diff --git a/ui/views/widget/root_view.h b/ui/views/widget/root_view.h
index 9ffd601..2db8a91 100644
--- a/ui/views/widget/root_view.h
+++ b/ui/views/widget/root_view.h
@@ -105,6 +105,7 @@ class VIEWS_EXPORT RootView : public View, public FocusTraversable {
   virtual void OnMouseMoved(const MouseEvent& event) OVERRIDE;
   virtual void OnMouseExited(const MouseEvent& event) OVERRIDE;
   virtual bool OnMouseWheel(const MouseWheelEvent& event) OVERRIDE;
+  virtual bool OnScrollEvent(const ScrollEvent& event) OVERRIDE;
   virtual ui::TouchStatus OnTouchEvent(const TouchEvent& event) OVERRIDE;
   virtual ui::GestureStatus OnGestureEvent(const GestureEvent& event) OVERRIDE;
   virtual void SetMouseHandler(View* new_mouse_handler) OVERRIDE;
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 31748ed..21c6735 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -1116,6 +1116,9 @@ bool Widget::OnMouseEvent(const MouseEvent& event) {
     case ui::ET_MOUSEWHEEL:
       return GetRootView()->OnMouseWheel(
           reinterpret_cast<const MouseWheelEvent&>(event));
+    case ui::ET_SCROLL:
+      return GetRootView()->OnScrollEvent(
+          reinterpret_cast<const ScrollEvent&>(event));
     default:
       return false;
   }