Add lifecycle observers for future mixin structures.

- Converted VisibilityLoggerMixin into a LifecyclerObservable so we
  don't have to call logger.onResume/onPause manually in most fragments.
- Observable will be useful when we provide logics across all
  fragment/activity, eg log lifecycle event latencies.
- Also added new tests for lifecycle component.

Bug: 30681529
Test: RunSettingsRoboTests

Change-Id: Ida39300aeb42f71b2e0bbfaebd0c51dc468cb5e8

src/com/android/settings/DeviceAdminSettings.java

@@ -64,7 +64,7 @@ public class DeviceAdminSettings extends ListFragment implements Instrumentable
     static final String TAG = "DeviceAdminSettings";
 
     private final VisibilityLoggerMixin mVisibilityLoggerMixin =
-            new VisibilityLoggerMixin(this);
+            new VisibilityLoggerMixin(getMetricsCategory());
     private DevicePolicyManager mDPM;
     private UserManager mUm;
 
@@ -135,7 +135,7 @@ public class DeviceAdminSettings extends ListFragment implements Instrumentable
     public void onResume() {
         super.onResume();
         final Activity activity = getActivity();
-        mVisibilityLoggerMixin.onResume(activity);
+        mVisibilityLoggerMixin.onResume();
         IntentFilter filter = new IntentFilter();
         filter.addAction(DevicePolicyManager.ACTION_DEVICE_POLICY_MANAGER_STATE_CHANGED);
         activity.registerReceiverAsUser(
@@ -158,7 +158,7 @@ public class DeviceAdminSettings extends ListFragment implements Instrumentable
     public void onPause() {
         final Activity activity = getActivity();
         activity.unregisterReceiver(mBroadcastReceiver);
-        mVisibilityLoggerMixin.onPause(activity);
+        mVisibilityLoggerMixin.onPause();
         super.onPause();
     }