Solve a possible NPE in the Documents provider

This commit follows an internal bug report to fix a NPE that would be
thrown in specific situations on specific devices. All callers should
be able to handle the returned null value but if they don't, we can
worry about that later down the line. This null value should not be
returned under normal circumstances anyway.

Change-Id: I274844bf07733643923d5729259f1d9d9cf75e54
Revert "Send out USER_PRESENT broadcast on screen on if lockscreen is disabled."

This reverts commit cf5a59b4b7898802a6dff08485e02d96f2a3211e.
Revert "Keyguard: We need to ensure that keyguard is showing as well to set the token"

This reverts commit 4978de66a15e2ac49da6544ae5c0b3e9c45fb0ef.
Revert "KeyguardViewMediator: Play lock screen sound sooner"

This reverts commit d0a316c8ccdbe233ebca90df6d78671525aa6ea7.
Merge remote-tracking branch 'aospa/kitkat' into kitkat
Base: Fix crash of SystemUI

Change-Id: Ie18faac4dce45eb2fe9ca07d628bed7cd0eafaab
Smoother Upload and Download Animation

Change-Id: I6e6409cc85ad951019dbac10156d4aed92f4c5bc