Make sure home activity gets resumed after started.

When there is only one activity and it gets paused, activity manager will
try resuming some other activity. If there is no other activity, it will
start home activity and try to resume it. This will fail, because the
activity stack doesn't want to enter recursive resuming. We need to
detect this situation and schedule additional resume of top activity
after home gets started.

Bug: 21500945
Change-Id: I6ca703f8d97bcc4001e7da4cd5a5db63bfb5c861

services/core/java/com/android/server/am/ActivityStackSupervisor.java

@@ -831,8 +831,18 @@ public final class ActivityStackSupervisor implements DisplayListener {
 
     void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason) {
         moveHomeStackTaskToTop(HOME_ACTIVITY_TYPE, reason);
-        startActivityLocked(null, intent, null, aInfo, null, null, null, null, 0, 0, 0, null,
-                0, 0, 0, null, false, null, null, null);
+        startActivityLocked(null /* caller */, intent, null /* resolvedType */, aInfo,
+                null /* voiceSession */, null /* voiceInteractor */, null /* resultTo */,
+                null /* resultWho */, 0 /* requestCode */, 0 /* callingPid */, 0 /* callingUid */,
+                null /* callingPackage */, 0 /* realCallingPid */, 0 /* realCallingUid */,
+                0 /* startFlags */, null /* options */, false /* componentSpecified */,
+                null /* outActivity */, null /* container */,  null /* inTask */);
+        if (inResumeTopActivity) {
+            // If we are in resume section already, home activity will be initialized, but not
+            // resumed (to avoid recursive resume) and will stay that way until something pokes it
+            // again. We need to schedule another resume.
+            scheduleResumeTopActivities();
+        }
     }
 
     final int startActivityMayWait(IApplicationThread caller, int callingUid,