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

1 files changed, 4 insertions, 0 deletions

diff --git a/ui/views/view.cc b/ui/views/view.cc
index 9541ab5..d200d03 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -846,6 +846,10 @@ bool View::OnMouseWheel(const MouseWheelEvent& event) {
   return false;
 }
 
+bool View::OnScrollEvent(const ScrollEvent& event) {
+  return false;
+}
+
 ui::TextInputClient* View::GetTextInputClient() {
   return NULL;
 }