ActiveDisplay: Remove unnecessary IPowerManager getter for screen state

This lookup method was incredibly slow and was causing some performance issues.
 Lets replace it with a boolean set by the broadcast receiver that already
handles some screen state behaviors.

Change-Id: I36cdb4122e4d3ec49d860e5a7b2af84516d69b21
ActiveDisplay: reduce some IO performed in regularly accessed methods

Previously inQuietHours() method was run nearly every time ActiveDisplay did anything.
Since it's optional if quiet hours settings will be observed we only need to run this method
when the user has chosen this behavior and futher we only need to do IO for the quiet hours
settings if quiet hours is enabled.

PS2: initialize uninitialzed variable mQuietTime and add missing return statement

Change-Id: I964fa0b56ef4296b6e9bf5c11d48c65a105e61eb
Merge "ActiveDisplay: Remove unnecessary IPowerManager getter for screen state" into kk44
Merge "ActiveDisplay: reduce some IO performed in regularly accessed methods" into kk44