API for connection type (Ethernet/WIFI/WWAN ...) in NetworkChangeNotifier.

net/base/network_change_notifier.h

Index: net/base/network_change_notifier.h
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index 477d1f718cd6114710dd1b0ea5e374273025061e..20ee6eb48aac242773d24714c3fb4e089a81e106 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -38,6 +38,18 @@ class NET_EXPORT NetworkChangeNotifier {
     CHANGE_DNS_WATCH_FAILED = 1 << 3,
   };
 
+  // Using the terminology of the Network Information API:
+  // http://www.w3.org/TR/netinfo-api.
+  enum ConnectionType {
+  CONNECTION_UNKNOWN, // A connection exists, but its type is unknown.
+  CONNECTION_ETHERNET,
+  CONNECTION_WIFI,
+  CONNECTION_2G,
+  CONNECTION_3G,
+  CONNECTION_4G,
+  CONNECTION_NONE     // No connection.
+};
+
   class NET_EXPORT IPAddressObserver {
    public:
     virtual ~IPAddressObserver() {}
@@ -53,20 +65,21 @@ class NET_EXPORT NetworkChangeNotifier {
     DISALLOW_COPY_AND_ASSIGN(IPAddressObserver);
   };
 
-  class NET_EXPORT OnlineStateObserver {
+  class NET_EXPORT ConnectionTypeObserver {
    public:
-    virtual ~OnlineStateObserver() {}
+    virtual ~ConnectionTypeObserver() {}
 
-    // Will be called when the online state of the system may have changed.
-    // See NetworkChangeNotifier::IsOffline() for important caveats about
-    // the unreliability of this signal.
-    virtual void OnOnlineStateChanged(bool online) = 0;
+  // Will be called when the connection type of the system has changed.
+  // See NetworkChangeNotifier::GetConnectionType() for important caveats
+  // about the unreliability of using this signal to infer the ability to
+  // reach remote sites.
+    virtual void OnConnectionTypeChanged(ConnectionType type) = 0;
 
    protected:
-    OnlineStateObserver() {}
+    ConnectionTypeObserver() {}
 
    private:
-    DISALLOW_COPY_AND_ASSIGN(OnlineStateObserver);
+    DISALLOW_COPY_AND_ASSIGN(ConnectionTypeObserver);
   };
 
   class NET_EXPORT DNSObserver {
@@ -86,10 +99,10 @@ class NET_EXPORT NetworkChangeNotifier {
 
   virtual ~NetworkChangeNotifier();
 
-  // See the description of NetworkChangeNotifier::IsOffline().
+  // See the description of NetworkChangeNotifier::GetConnectionType().
   // Implementations must be thread-safe. Implementations must also be
   // cheap as this could be called (repeatedly) from the IO thread.
-  virtual bool IsCurrentlyOffline() const = 0;
+  virtual ConnectionType GetCurrentConnectionType() const = 0;
 
   // Replaces the default class factory instance of NetworkChangeNotifier class.
   // The method will take over the ownership of |factory| object.
@@ -103,6 +116,15 @@ class NET_EXPORT NetworkChangeNotifier {
   // which might try to use it.
   static NetworkChangeNotifier* Create();
 
+  // Returns the connection type.
+  // A return value of |CONNECTION_NONE| is a pretty strong indicator that the
+  // user won't be able to connect to remote sites. However, another return
+  // value doesn't imply that the user will be able to connect to remote sites;
+  // even if some link is up, it is uncertain whether a particular connection
+  // attempt to a particular remote site will be successful.
+  static ConnectionType GetConnectionType();
+
+  // Convenience method to determine if the user is offline.
   // Returns true if there is currently no internet connection.
   //
   // A return value of |true| is a pretty strong indicator that the user
@@ -110,7 +132,9 @@ class NET_EXPORT NetworkChangeNotifier {
   // |false| is inconclusive; even if some link is up, it is uncertain
   // whether a particular connection attempt to a particular remote site
   // will be successfully.
-  static bool IsOffline();
+  static bool IsOffline() {
+    return GetConnectionType() == CONNECTION_NONE;
+  }
 
   // Returns true if DNS watcher is operational.
   static bool IsWatchingDNS();
@@ -125,7 +149,7 @@ class NET_EXPORT NetworkChangeNotifier {
   // been called (as long as it doesn't race the Create() call on another
   // thread), in which case it will simply do nothing.
   static void AddIPAddressObserver(IPAddressObserver* observer);
-  static void AddOnlineStateObserver(OnlineStateObserver* observer);
+  static void AddConnectionTypeObserver(ConnectionTypeObserver* observer);
   static void AddDNSObserver(DNSObserver* observer);
 
   // Unregisters |observer| from receiving notifications.  This must be called
@@ -136,7 +160,7 @@ class NET_EXPORT NetworkChangeNotifier {
   // been destroyed, if the call doesn't race the notifier's destruction, but
   // there's no reason to use the API in this risky way, so don't do it.
   static void RemoveIPAddressObserver(IPAddressObserver* observer);
-  static void RemoveOnlineStateObserver(OnlineStateObserver* observer);
+  static void RemoveConnectionTypeObserver(ConnectionTypeObserver* observer);
   static void RemoveDNSObserver(DNSObserver* observer);
 
   // Allow unit tests to trigger notifications.
@@ -153,7 +177,7 @@ class NET_EXPORT NetworkChangeNotifier {
   // happens asynchronously, even for observers on the current thread, even in
   // tests.
   static void NotifyObserversOfIPAddressChange();
-  static void NotifyObserversOfOnlineStateChange();
+  static void NotifyObserversOfConnectionTypeChange();
   static void NotifyObserversOfDNSChange(unsigned detail);
 
  private:
@@ -179,8 +203,8 @@ class NET_EXPORT NetworkChangeNotifier {
 
   const scoped_refptr<ObserverListThreadSafe<IPAddressObserver> >
       ip_address_observer_list_;
-  const scoped_refptr<ObserverListThreadSafe<OnlineStateObserver> >
-      online_state_observer_list_;
+  const scoped_refptr<ObserverListThreadSafe<ConnectionTypeObserver> >
+      connection_type_observer_list_;
   const scoped_refptr<ObserverListThreadSafe<DNSObserver> >
       resolver_state_observer_list_;