Fix a regression in r56766  CustomButton::OnKeyEvent should return false when the event is not handled
Fix a regression in r56766
 CustomButton::OnKeyEvent should return false when the event is not handled

BUG=chromium-os:6290
TEST=none

Review URL: http://codereview.chromium.org/3276007

git-svn-id: http://src.chromium.org/svn/trunk/src@58111 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: a0c4a7ef1fd0e8acebb160f189026831b77f1180
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser