Fix right click to context menu behavior of View.

When the View opens the context menu, the mouse-down event is
already handled. Therefore, the next ACTION_UP should be canceled,
otherwise, single right click shows the context menu and then
invokes the normal click actions.

Also, the right-down event should always be consumed regardless
of the context menu support. "the right click opens the context
menu on some views, but it behaves as a normal click on some
other views" would confuse users.

Bug: 19641497
Change-Id: Ibbc18fe641745cf42382129b81858d8f3d14768b