Helper functions in NetworkChangeNotifier related to WWAN use

On iOS, this is used to disable certain features when WWAN is active in order to
save network traffic and/or battery.

BUG=145954


Review URL: https://chromiumcodereview.appspot.com/11115009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@165929 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 36 insertions, 3 deletions

diff --git a/net/base/network_change_notifier.cc b/net/base/network_change_notifier.cc
index ab3fd43..e8dd120 100644
--- a/net/base/network_change_notifier.cc
+++ b/net/base/network_change_notifier.cc
@@ -298,6 +298,30 @@ NetworkChangeNotifier::GetAddressTracker() {
 #endif
 
 // static
+bool NetworkChangeNotifier::IsOffline() {
+   return GetConnectionType() == CONNECTION_NONE;
+}
+
+// static
+bool NetworkChangeNotifier::IsConnectionCellular(ConnectionType type) {
+  bool is_cellular = false;
+  switch (type) {
+    case CONNECTION_2G:
+    case CONNECTION_3G:
+    case CONNECTION_4G:
+      is_cellular =  true;
+      break;
+    case CONNECTION_UNKNOWN:
+    case CONNECTION_ETHERNET:
+    case CONNECTION_WIFI:
+    case CONNECTION_NONE:
+      is_cellular = false;
+      break;
+  }
+  return is_cellular;
+}
+
+// static
 NetworkChangeNotifier* NetworkChangeNotifier::CreateMock() {
   return new MockNetworkChangeNotifier();
 }
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index 21aa1a1..84e399e 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -111,6 +111,10 @@ class NET_EXPORT NetworkChangeNotifier {
   // 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.
+  // The returned value only describes the connection currently used by the
+  // device, and does not take into account other machines on the network. For
+  // example, if the device is connected using Wifi to a 3G gateway to access
+  // the internet, the connection type is CONNECTION_WIFI.
   static ConnectionType GetConnectionType();
 
   // Retrieve the last read DnsConfig. This could be expensive if the system has
@@ -130,9 +134,14 @@ 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() {
-    return GetConnectionType() == CONNECTION_NONE;
-  }
+  static bool IsOffline();
+
+  // Returns true if |type| is a cellular connection.
+  // Returns false if |type| is CONNECTION_UNKNOWN, and thus, depending on the
+  // implementation of GetConnectionType(), it is possible that
+  // IsConnectionCellular(GetConnectionType()) returns false even if the
+  // current connection is cellular.
+  static bool IsConnectionCellular(ConnectionType type);
 
   // Like Create(), but for use in tests.  The mock object doesn't monitor any
   // events, it merely rebroadcasts notifications when requested.