window: Adds a Sustained Performance Mode window flag.

Adds setSustainedPerformanceMode(boolean) API for applications to set
the mode for a given window. The mode will be disabled automatically when the
window is no longer in focus.

Bug: 28150358
Change-Id: Ibe8bc564eeaaccbcaad5c4f792cda16da931dffd
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
7 files changed