Merge "Do not allow app to start background activity after stop app switches triggered" into qt-dev

am: 02d9b9c35b

Change-Id: Ib4c2d91a12be63cea87f3bee198c17965d217f93

services/core/java/com/android/server/wm/ActivityTaskManagerService.java

@@ -509,6 +509,12 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
      */
     private boolean mDidAppSwitch;
 
+    /**
+     * Last stop app switches time, apps finished before this time cannot start background activity
+     * even if they are in grace period.
+     */
+    private long mLastStopAppSwitchesTime;
+
     IActivityController mController = null;
     boolean mControllerIsAMonkey = false;
 
@@ -4749,6 +4755,7 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
         enforceCallerIsRecentsOrHasPermission(STOP_APP_SWITCHES, "stopAppSwitches");
         synchronized (mGlobalLock) {
             mAppSwitchesAllowedTime = SystemClock.uptimeMillis() + APP_SWITCH_DELAY_TIME;
+            mLastStopAppSwitchesTime = SystemClock.uptimeMillis();
             mDidAppSwitch = false;
             getActivityStartController().schedulePendingActivityLaunches(APP_SWITCH_DELAY_TIME);
         }
@@ -4765,6 +4772,10 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
         }
     }
 
+    long getLastStopAppSwitchesTime() {
+        return mLastStopAppSwitchesTime;
+    }
+
     void onStartActivitySetDidAppSwitch() {
         if (mDidAppSwitch) {
             // This is the second allowed switch since we stopped switches, so now just generally

services/core/java/com/android/server/wm/WindowProcessController.java

@@ -402,12 +402,18 @@ public class WindowProcessController extends ConfigurationContainer<Configuratio
         if (mAllowBackgroundActivityStarts) {
             return true;
         }
-        // allow if any activity in the caller has either started or finished very recently
+        // allow if any activity in the caller has either started or finished very recently, and
+        // it must be started or finished after last stop app switches time.
         final long now = SystemClock.uptimeMillis();
         if (now - mLastActivityLaunchTime < ACTIVITY_BG_START_GRACE_PERIOD_MS
                 || now - mLastActivityFinishTime < ACTIVITY_BG_START_GRACE_PERIOD_MS) {
+            // if activity is started and finished before stop app switch time, we should not
+            // let app to be able to start background activity even it's in grace period.
+            if (mLastActivityLaunchTime > mAtm.getLastStopAppSwitchesTime()
+                    || mLastActivityFinishTime > mAtm.getLastStopAppSwitchesTime()) {
                 return true;
             }
+        }
         // allow if the proc is instrumenting with background activity starts privs
         if (mInstrumentingWithBackgroundActivityStartPrivileges) {
             return true;