Fix race condition in NetworkChangeNotifier on Android.

net/android/network_change_notifier_android.h

 // Copyright (c) 2012 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 NET_ANDROID_NETWORK_CHANGE_NOTIFIER_ANDROID_H_
 #define NET_ANDROID_NETWORK_CHANGE_NOTIFIER_ANDROID_H_
 
 #include "base/android/scoped_java_ref.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/synchronization/lock.h"
 #include "net/base/network_change_notifier.h"
 
 namespace net {
 namespace android {
 
 class NetworkChangeNotifier : public net::NetworkChangeNotifier {
  public:
-  NetworkChangeNotifier();
   virtual ~NetworkChangeNotifier();
 
-  void NotifyObservers(JNIEnv* env, jobject obj);
+  // Called from Java on the UI thread.
+  void NotifyObservers(JNIEnv* env, jobject obj, int new_connection_type);
+  jint GetConnectionType(JNIEnv* env, jobject obj);
 
   static bool Register(JNIEnv* env);
 
  private:
+  friend class NetworkChangeNotifierFactory;
+
+  NetworkChangeNotifier();
+
   void CreateJavaObject(JNIEnv* env);
 
+  void SetConnectionType(int connection_type);
+
   // NetworkChangeNotifier:
   virtual net::NetworkChangeNotifier::ConnectionType
       GetCurrentConnectionType() const OVERRIDE;
 
   base::android::ScopedJavaGlobalRef<jobject> java_network_change_notifier_;
+  // TODO(pliard): Use an atomic integer for the connection type without the
+  // lock once a non-subtle atomic integer is available under base/. That might
+  // never happen though.

[szym, 2012/09/19 18:46:55]

Add relevant reference to crbug.com/

[Philippe, 2012/09/19 20:57:56]

Done.

+  mutable base::Lock lock_;  // Protects the state below.
+  // Wrote from the UI thread, read from any thread.

[szym, 2012/09/19 18:46:55]

nit: "Written"

[Philippe, 2012/09/19 20:57:56]

Oops :)

+  int connection_type_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
 };
 
 }  // namespace android
 }  // namespace net
 
 #endif  // NET_ANDROID_NETWORK_CHANGE_NOTIFIER_ANDROID_H_