Reduce object allocations in WM in some frequently called methods

With the use of lambdas to get all windows in the window container
hierarchy, we need to be careful in frequently called code paths to
make sure the number of objects we allocate isn't crazy. This CL
converts some commonly called code paths that use lambda to use a
method reference for the lambda so we only need to allocate once vs.
each time the code path is executed.

Test: Perform some common operations on the phone and make sure
      the object allocations that show-up in Allocator Tracker for
      window manager seems reasonable

Change-Id: Ie0f245980de96ec68a4e62e76130db7d98c3f7d9