ash: Add launcher overflow bubble.

- Host a LauncherView in bubble to display overflown items;
- Mouse wheel and two-finger scroll to scroll the LauncherView in bubble in case overflow bubble is overflown;
- Fit bubble when items are added/removed;
- Keep launcher bar on screen when the bubble is shown;

BUG=128054
TEST=Verify launcher overflown items are in a bubble instead of menu.


Review URL: https://chromiumcodereview.appspot.com/10659003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146460 0039d316-1c4b-4281-b951-d872f2087c98
bool LauncherView::SameDragType(LauncherItemType typea,
                                LauncherItemType typeb) const {
  switch (typea) {
    case TYPE_TABBED:
    case TYPE_APP_PANEL:
    case TYPE_PLATFORM_APP:
      return (typeb == TYPE_TABBED ||
          typeb == TYPE_APP_PANEL ||
          typeb == TYPE_PLATFORM_APP);
    case TYPE_APP_SHORTCUT:
    case TYPE_APP_LIST:
    case TYPE_BROWSER_SHORTCUT:
      return typeb == typea;
  }
  NOTREACHED();
  return false;
}

bool LauncherView::SameDragType(LauncherItemType typea,
                                LauncherItemType typeb) const {
  switch (typea) {
    case TYPE_TABBED:
    case TYPE_APP_PANEL:
    case TYPE_PLATFORM_APP:
      return (typeb == TYPE_TABBED ||
          typeb == TYPE_APP_PANEL ||
          typeb == TYPE_PLATFORM_APP);
    case TYPE_APP_SHORTCUT:
    case TYPE_APP_LIST:
    case TYPE_BROWSER_SHORTCUT:
      return typeb == typea;
  }
  NOTREACHED();
  return false;
}
