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

content/browser/android/background_sync_network_observer_android.h

Index: content/browser/android/background_sync_network_observer_android.h
diff --git a/content/browser/android/background_sync_network_observer_android.h b/content/browser/android/background_sync_network_observer_android.h
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index 0000000000000000000000000000000000000000..f36f32376090045d2dd8b83066c310c8e9966a85
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+++ b/content/browser/android/background_sync_network_observer_android.h
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+// 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 is backed by a NetworkChangeNotifier
+// that listens for network events even when the browser is paused, unlike the
+// standard NetworkChangeNotifier. 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 via PostMessage when the network connection changes.
+  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| provided to the
+  // constructor.
+  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_