Handle adding EmbeddedWindows to host windows without an activity

If the host window does not have a backing activity or we are granting input to
surface with out a host window, don't provide an application handle to input.

Test: atest CtsWindowManagerDeviceTestCases:WindowlessWmTests
Change-Id: I6efd1ccfc5688ba3532251df2685156fc030e8ba
1 file changed