frameworks/base/: Fix black wallpaper issue when home pressed.

In the specified usecase, there is a completely new set of
windows that appear on the screen during rotation. And the
existing code in the framework ignores the drawstate of the
hidden windows.

Wait till the drawState is ready for the hidden windows also.

CRs-Fixed: 521758

Change-Id: Ibd96502059c84210ad84ecb03aac5eca28f3c9fe
Merge "frameworks/base/: Fix black wallpaper issue when home pressed." into jb3