[BackgroundSync] Trigger Background Sync events when Chrome is backgrounded on Android

content/browser/background_sync/background_sync_manager.h

Index: content/browser/background_sync/background_sync_manager.h
diff --git a/content/browser/background_sync/background_sync_manager.h b/content/browser/background_sync/background_sync_manager.h
index a541c0bd40edeccb0692b7add383c498dbaed802..5080ba81ade9d5e9a8ea3fadea1df8dd89be407e 100644
--- a/content/browser/background_sync/background_sync_manager.h
+++ b/content/browser/background_sync/background_sync_manager.h
@@ -99,6 +99,10 @@ class CONTENT_EXPORT BackgroundSyncManager
                              const GURL& pattern) override;
   void OnStorageWiped() override;
 
+  BackgroundSyncNetworkObserver* GetNetworkObserverForTesting() {
+    return network_observer_.get();
+  }
+
  protected:
   // A registration might be referenced by the client longer than
   // the BackgroundSyncManager needs to keep track of it (e.g., the event has