Prevent dream service finishSelf before it was attached

Bring back stopSelf logic to prevent dream service finishSelf before any
token attached.

Fix: 150818348
Test: manual test, won't throw exp while leaving dream service.
Merged-In: I31bb4f32013b9fa0aa2263b94117060e4d3a7341
Change-Id: I31bb4f32013b9fa0aa2263b94117060e4d3a7341

core/java/android/service/dreams/DreamService.java

@@ -906,15 +906,21 @@ public class DreamService extends Service implements Window.Callback {
             if (!mActivity.isFinishing()) {
                 // In case the activity is not finished yet, do it now.
                 mActivity.finishAndRemoveTask();
+            }
             return;
         }
-        } else if (!mWindowless) {
-            Slog.w(TAG, "Finish was called before the dream was attached.");
-        }
 
-        if (!mFinished) {
+        if (mFinished) {
+            return;
+        }
         mFinished = true;
 
+        if (mDreamToken == null) {
+            Slog.w(TAG, "Finish was called before the dream was attached.");
+            stopSelf();
+            return;
+        }
+
         try {
             // finishSelf will unbind the dream controller from the dream service. This will
             // trigger DreamService.this.onDestroy and DreamService.this will die.
@@ -923,7 +929,6 @@ public class DreamService extends Service implements Window.Callback {
             // system server died
         }
     }
-    }
 
     /**
      * Wakes the dream up gently.