Default to using hardware layer during fade transition.

Bug 17499864

When hasOverlappingRendering() is true, a layer is used to
to fade views because performance can be much worse then.
When hasOverlappingRendering() is false, the performance
is not hurt and a layer is not used.

Change-Id: If3fb1c23ffc8d0bef85c9d16df6c26ff4bbd49ac