Speed up initiating resizing.

This CL effectively starts resizing on mouse down click on the window
edges by forcing reporting a resize before any bounds changes.

As a result the app will kick in the backdrop renderer before
configuration change applies, so before a potential activity restart.

Test: Try to resize Play store quickly. Should resize smoother.
Bug: 64327032
Change-Id: I668ea9f4c264e18ddee3ed9e8d03365631f10417