Don't set return to recents on every resume

Checking for previous task to be the Recents activity every time
through resumeTopActivityLocked() leads to missetting the
mTaskToReturnTo to Recents for Recents. Instead check for
Recents launching a task in moveTaskToFront and startActivity.

Fixes bug 15832448.

Change-Id: Ib64fe26f3fd3fdcd878edafb041928ec02757e63
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 73266bc..e7f5720 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -1981,6 +1981,9 @@
         mService.grantUriPermissionFromIntentLocked(callingUid, r.packageName,
                 intent, r.getUriPermissionsLocked(), r.userId);
 
+        if (sourceRecord != null && sourceRecord.isRecentsActivity()) {
+            r.task.setTaskToReturnTo(RECENTS_ACTIVITY_TYPE);
+        }
         if (newTask) {
             EventLog.writeEvent(EventLogTags.AM_CREATE_TASK, r.userId, r.task.taskId);
         }