Fix 5466793: Fix memory leak in system process when face lock is enabled.

Previously, the code was not unregistering the callback when we unlocked
the device, which kept a reference to LockPatternKeyguardView indirectly
by a reference to mFaceLockCallback.

It now correcly removes the callback when we unlock the device.

Change-Id: Ie592d007a1dfc2416b9e8956aba2c34e3d0120ee

Author: Jim Miller

core/java/com/android/internal/policy/IFaceLockInterface.aidl

@@ -23,4 +23,5 @@ interface IFaceLockInterface {
     void startUi(IBinder containingWindowToken, int x, int y, int width, int height);
     void stopUi();
     void registerCallback(IFaceLockCallback cb);
+    void unregisterCallback(IFaceLockCallback cb);
 }

policy/src/com/android/internal/policy/impl/LockPatternKeyguardView.java

@@ -782,6 +782,15 @@ public void cleanUp() {
             mUnlockScreen = null;
         }
         mUpdateMonitor.removeCallback(this);
+        if (mFaceLockService != null) {
+            try {
+                mFaceLockService.unregisterCallback(mFaceLockCallback);
+            } catch (RemoteException e) {
+                // Not much we can do
+            }
+            stopFaceLock();
+            mFaceLockService = null;
+        }
     }
 
     private boolean isSecure() {
@@ -1206,6 +1215,13 @@ public void stopAndUnbindFromFaceLock() {
 
             if (mBoundToFaceLockService) {
                 if (DEBUG) Log.d(TAG, "before unbind from FaceLock service");
+                if (mFaceLockService != null) {
+                    try {
+                        mFaceLockService.unregisterCallback(mFaceLockCallback);
+                    } catch (RemoteException e) {
+                        // Not much we can do
+                    }
+                }
                 mContext.unbindService(mFaceLockConnection);
                 if (DEBUG) Log.d(TAG, "after unbind from FaceLock service");
                 mBoundToFaceLockService = false;