Move logic about computing window frames to the client side

This CL moves the logic about clipping window frames by display cutouts
to the client side. Without this, the very first window frame might be
incorrect, and that can make the framework dispatch the wrong insets to
the app.

This CL is also a step to layout windows at the client side, and
introduces a new class, WindowLayout, which will contain all the logic
about computing the window frame. For now, it only computes the
display frame and the parent frame, but eventually, it will compute the
window frame.

Bug: 197245443
Bug: 161810301
BUg: 175858823
Test: 1. Steps in b/197245443
      2. atest DisplayPolicyLayoutTests
Change-Id: Icafe76112547f4558c7397a1fc5fd08d87639a4d