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

content/browser/android/background_sync_network_observer_android.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_ANDROID_BACKGROUND_SYNC_NETWORK_OBSERVER_ANDROID_H_
+#define CONTENT_BROWSER_ANDROID_BACKGROUND_SYNC_NETWORK_OBSERVER_ANDROID_H_
+
+#include "base/android/jni_android.h"
+#include "base/android/scoped_java_ref.h"
+#include "content/browser/background_sync/background_sync_network_observer.h"
+
+namespace content {
+
+// BackgroundSyncNetworkObserverAndroid is a specialized
+// BackgroundSyncNetworkObserver which always uses the actual connectivity state

[jkarlin, 2015/08/28 01:19:48]

"always uses the actual connectivity state" sounds like the other observer
doesn't use the actual connectivity state.  Perhaps rephrase to, "backed by a
NetworkChangeNotifier that listens for network events even when the browser is
paused, unlike the standard NetworkChangeNotifier".

On that note, we should probably not listen for connectivity events while paused
if there aren't any background syncs pending. Please add a bug/todo for that.

[iclelland, 2015/08/31 16:00:52]

Done.

+// of the device to determine whether sync events are eligible to be fired. This
+// ensures that sync events can be fired even when the browser is backgrounded,
+// and other network observers are disabled.
+class BackgroundSyncNetworkObserverAndroid
+    : public BackgroundSyncNetworkObserver {
+ public:
+  // Creates a BackgroundSyncNetworkObserver. |network_changed_callback| is
+  // called when the network connection changes asynchronously via PostMessage.

[jkarlin, 2015/08/28 01:19:48]

can probably remove 'asynchronously' without losing anything

[iclelland, 2015/08/31 16:00:52]

Done.

+  BackgroundSyncNetworkObserverAndroid(
+      const base::Closure& network_changed_callback);
+
+  ~BackgroundSyncNetworkObserverAndroid() override;
+
+  static bool RegisterNetworkObserver(JNIEnv* env);
+
+  // Called from BackgroundSyncNetworkObserver.java on the JNI thread whenever
+  // the connection type changes. This updates the current connection type seen
+  // by this class and calls the |network_changed_callback|.

[jkarlin, 2015/08/28 01:19:48]

calls |network_changed_callback| provided to the constructor

[iclelland, 2015/08/31 16:00:52]

Done.

+  void NotifyConnectionTypeChanged(JNIEnv* env,
+                                   jobject jcaller,
+                                   jint new_connection_type);
+
+ private:
+  base::android::ScopedJavaLocalRef<jobject> observer_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_ANDROID_BACKGROUND_SYNC_NETWORK_OBSERVER_ANDROID_H_