Fix crash upon stopping Cast

Bug: internal b/112284077
Change-Id: I9b30669d0864f5f72369ae76e353200609108e5f
Reviewed-on: https://chromium-review.googlesource.com/1167970Reviewed-by: Simeon Anfinrud <sanfin@chromium.org>
Commit-Queue: Andrei Pascovici <apascovici@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582999}

chromecast/browser/android/apk/src/org/chromium/chromecast/shell/CastWebContentsService.java

@@ -65,10 +65,10 @@ public class CastWebContentsService extends Service {
     }
 
     @Override
-    public void onDestroy() {
-        if (DEBUG) Log.d(TAG, "onDestroy");
+    public boolean onUnbind(Intent intent) {
+        if (DEBUG) Log.d(TAG, "onUnbind");
         mWebContentsState.reset();
-        super.onDestroy();
+        return super.onUnbind(intent);
     }
 
     @Override