tree 9cf2ccc9fb45be608329b963b3f960f506c882cd
parent 6cf6af0299f7e48bc5bcdcd6a6c0f5a8725e9411
author Robert Carr <racarr@google.com> 1480359060 -0800
committer Robert Carr <racarr@google.com> 1485284260 -0800

SurfaceFlinger and libgui: Switch Z-order to signed type.

In preparation for SurfaceFlinger child layers. In that model
children's Z order will be relative to their parent. We need
negative Z values to represent children stacking below their
parent (e.g. SurfaceView). Java side already uses signed types
strangely enough.

Test: Basically a refactoring. SurfaceFlinger still works.
Change-Id: Ifcece69f6f9d917cbf5238a59f8e5de1e8ba6a25