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

content/browser/android/background_sync_network_observer_android.cc

+// 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.
+
+#include "content/browser/android/background_sync_network_observer_android.h"
+
+#include "jni/BackgroundSyncNetworkObserver_jni.h"
+
+namespace content {
+
+// static
+bool BackgroundSyncNetworkObserverAndroid::Observer::RegisterNetworkObserver(
+    JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+BackgroundSyncNetworkObserverAndroid::Observer::Observer(
+    base::Callback<void(net::NetworkChangeNotifier::ConnectionType)> callback)
+    : callback_(callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);

[jkarlin, 2015/09/16 20:13:26]

It seems like the code here and below in this function should be on the UI
thread.

If you had a Create function and an Init function, you could have something
like:

scoped_refptr<BSNOA::Observer::Observer> Create() {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  scoped_refptr<BSNOA::Observer::Observer> observer(new
BSNOA::Observer::Observer());
  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
      base::Bind(&BSNOA::Observer::Init, observer);
  return observer;
}

And then the JNI code would all be called on the UI thread. What do you think?

[iclelland, 2015/09/18 15:46:28]

That's a great idea -- thanks for that! I've added a static Create, and made the
constructor private for this now. Also, the Create method takes the callback
parameter, and passes it through to the constructor.

Done.

+  // Attach a Java BackgroundSyncNetworkObserver object. Its lifetime will be
+  // scoped to the lifetime of this object.
+  JNIEnv* env = base::android::AttachCurrentThread();
+  base::android::ScopedJavaLocalRef<jobject> obj =
+      Java_BackgroundSyncNetworkObserver_createObserver(
+          env, base::android::GetApplicationContext(),
+          reinterpret_cast<jlong>(this));
+  observer_ = obj;
+}
+
+BackgroundSyncNetworkObserverAndroid::Observer::~Observer() {
+}
+
+void BackgroundSyncNetworkObserverAndroid::Observer::
+    NotifyConnectionTypeChanged(JNIEnv* env,
+                                jobject jcaller,
+                                jint new_connection_type) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(callback_,
+                 static_cast<net::NetworkChangeNotifier::ConnectionType>(
+                     new_connection_type)));
+}
+
+BackgroundSyncNetworkObserverAndroid::BackgroundSyncNetworkObserverAndroid(
+    const base::Closure& network_changed_callback)
+    : BackgroundSyncNetworkObserver(network_changed_callback),
+      weak_ptr_factory_(this) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // Remove the observer attached by the NetworkObserver constructor
+  net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
+
+  observer_ = new Observer(
+      base::Bind(&BackgroundSyncNetworkObserverAndroid::OnNetworkChanged,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+BackgroundSyncNetworkObserverAndroid::~BackgroundSyncNetworkObserverAndroid() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+}
+}  // namespace content