Remove unused API on IWindowSession, prepare for multi-display.

Scan on code base and found those API are not be used
anymore, and IWindowSession only be used in frameworks. Should be
able to remove them if needed.

Bug:111361793
Test: atest CtsWindowManagerDeviceTestCases
Test: atest CtsActivityManagerDeviceTestCases
Change-Id: Idbf680ae68d21e055d9ccfa33aea4a73891ddd14
2 files changed