Fix a JNI local reference leak in MediaDrm

A reference leak was found in the subtitle usecase that also
applies to android_media_MediaDrm.cpp
(Code taken from the similar fix in android_media_MediaPlayer.cpp)

Change-Id: Icc4b25e4adc9a600ff4ac99a7a8478bb55a6e348
Keyguard: don't refresh ui when screen off

KeyguardStatusView is doing refresh all the time,
which cause high power when screen off.

PatchSet:
- We turn of the refresh when screen is off which is a good
  idea. But we should force latest next refresh when screen turns
  on. Du that a timechanged refresh maybe comes a bit later.

Change-Id: Ifabdde4419a23e919cd52fe77e78ec3160575af1
ProcessList: use different polling interval when screen off

We are using the same time interval for both screen off and screen on.
For process on top: ActivityManager.PROCESS_STATE_TOP, we will poll PSS
information every 120 sec.
During polling PSS, we are grep /proc/%d/smaps which is a 10k lines file.
This cost quite a lot of CPU resource. But when screen off, we don't need to update
TOP process PSS so frequently since we are not operating it. Lower polling
circle to every 15min to reduce power.

Change-Id: Ia4cd26290d44d066f034d5270ce5523650a3c493
onAccountsUpdated shouldn't be called back after listener unregistered

There is a problem of AccountManager that onAccountsUpdated() is
called back even after the OnAccountsUpdatedListener is unregistered.
It may cause application crash.

For example, when rotating a tablet 180 degree with Settings apk
running, com.android.settings.Settings is re-launched 2 times
successively. (Destroy->Create->Destroy->Create)
It repeats adding&removing OnAccountUpdatedListener.

When dialog was being opened in the following cases,
NullPointerException at BackStackRecord.getBreadCrumbTitle()
was happened on 10 inch tablet which has 2 panes on Settings.
* Settings > Language&input > Language
* Settings > Language & input > Text-to-speech output > Speech rate
* Settings > Wi-Fi > Menu > Advanced > Keep Wi-Fi on during sleep
* Settings > Wi-Fi > Menu > Wi-Fi Direct > Rename device

This fix prevents the undesirable callback.

Change-Id: I081f69c90539cca821cf686b4587495135f375e4