Fixed incorrect calculation of dirty invalidation area

Padding was already taken into consideration before calling
invalidateDrawable in ProgressBar.

Change-Id: I75f25b0b7ee87d394422c58888ed3a1cca5d06a8
Fix to NullPointerException on move back in ActivityStack.

In ActivityTask.moveTaskToBackLocked NullPointerException may occur
when moving back with only current Activity in stack. This due to a
condition that may trigger despite a TaskRecord being null and then
attempt accessing the TaskRecord.mOnTopOfHome variable.

TaskRecord task may be set to null when no resumed activity remain.

Resolved by assuring that flag mOnTopOfHome is instead set to false
for current TaskRecord in case where there are no remaining activities
above home.

The above bug has already been corrected in the following commit,
ada62fca51d314cefe2c5da4e007df5b9abf320d, but it does not set the
cottect value to mTopOfHome for the current taks, see below.

Variable mOnTopOfHome will not be set to false in situations where
stack is of size 1 or less and task is null, perhaps from already
having finished current activity.

To avoid current TaskRecord maintaining value mOnTopOfHome to true
after launching Home this variable is set to false.

Impact should not be major due to correction earlier that makes sure
that there is always a TaskRecord.mOnTopOfHome set to true above Home
activity but if not correctly set for current task still gives a
possibility of bad behavior.

Change-Id: Ie86ad99c188aaa05b0de9d58eaa16c42b6fc4341
Fix error checking in MemoryFile.

mmap returns MAP_FAILED on failures, not 0 (NULL).
Also, convert some C style casts to C++ since they
make intent clearer.

Change-Id: I367993c73e9ee576f11ebe76e530d2c2f27c662d
Keyguard: do not allow to delete the system widget if widgets are disabled

We overwrite the default widget with our own one. In this case it is detected
as a normal widget even though it widgets are disabled and starts listening to
longpress events

Whatever check if widgets are disabled. If this is the case do not allow any
longpress events

Change-Id: I471664bac6ca1f8e57efe4904a385904c40486db
Merge "Keyguard: fix not shown overlay widgets from system" into cm-11.0
Merge "Keyguard: let the user drag the challenge down if widgets are disabled" into cm-11.0