Add WiFi SSID getter to NetworkChangeNotifier.

net/base/address_tracker_linux.h

Index: net/base/address_tracker_linux.h
diff --git a/net/base/address_tracker_linux.h b/net/base/address_tracker_linux.h
index 29cb8c0437d20c841c0c51b630570e97d14fdcd0..cf430a92dd684c4df8006f2fa0f987d77274fc7c 100644
--- a/net/base/address_tracker_linux.h
+++ b/net/base/address_tracker_linux.h
@@ -12,6 +12,7 @@
 #undef net
 
 #include <map>
+#include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
@@ -34,6 +35,9 @@ class NET_EXPORT_PRIVATE AddressTrackerLinux :
  public:
   typedef std::map<IPAddressNumber, struct ifaddrmsg> AddressMap;
 
+  // A function that returns the SSID of an interface given the interface name.
+  typedef std::string (*GetInterfaceSSIDFunction)(const std::string& ifname);
+
   // Non-tracking version constructor: it takes a snapshot of the
   // current system configuration. Once Init() returns, the
   // configuration is available through GetOnlineLinks() and
@@ -65,6 +69,11 @@ class NET_EXPORT_PRIVATE AddressTrackerLinux :
   // Safe to call from any thread, but will block until Init() has completed.
   NetworkChangeNotifier::ConnectionType GetCurrentConnectionType();
 
+  // Implementation of NetworkChangeNotifierLinux::GetCurrentWiFiSSID().
+  // Safe to call from any thread. Doesn't wait for initialization to complete,
+  // so may return empty string.
+  std::string GetCurrentWiFiSSID();
+
   // Returns the name for the interface with interface index |interface_index|.
   // |buf| should be a pointer to an array of size IFNAMSIZ. The returned
   // pointer will point to |buf|. This function acts like if_indextoname which
@@ -72,6 +81,15 @@ class NET_EXPORT_PRIVATE AddressTrackerLinux :
   // with exclusively talking to the kernel and not the C library.
   static char* GetInterfaceName(int interface_index, char* buf);
 
+  // Gets the current Wi-Fi SSID based on |interfaces|. Returns
+  // empty string if there are no interfaces or if two interfaces have different
+  // connection types. Otherwise returns the SSID of all interfaces if they have
+  // the same SSID. This is adapted from
+  // NetworkChangeNotifier::ConnectionTypeFromInterfaceList.
+  static std::string ConnectionSSIDFromInterfaceList(
+      const NetworkInterfaceList& interfaces,
+      GetInterfaceSSIDFunction get_interface_ssid);
+
  private:
   friend class AddressTrackerLinuxTest;
 
@@ -125,8 +143,9 @@ class NET_EXPORT_PRIVATE AddressTrackerLinux :
   // Does |interface_index| refer to a tunnel interface?
   bool IsTunnelInterface(int interface_index) const;
 
-  // Updates current_connection_type_ based on the network list.
-  void UpdateCurrentConnectionType();
+  // Updates current_connection_type_ and current_wifi_ssid_ based on the
+  // network list.
+  void UpdateCurrentConnectionTypeAndSSID();
 
   // Gets the name of an interface given the interface index |interface_index|.
   // May return empty string if it fails but should not return NULL. This is
@@ -151,6 +170,10 @@ class NET_EXPORT_PRIVATE AddressTrackerLinux :
   bool connection_type_initialized_;
   base::ConditionVariable connection_type_initialized_cv_;
   NetworkChangeNotifier::ConnectionType current_connection_type_;
+
+  base::Lock wifi_ssid_lock_;
+  std::string current_wifi_ssid_;
+
   bool tracking_;
 
   // Used to verify single-threaded access in non-tracking mode.