Add a new GetInstance() method for singleton classes under chrome/service and /net.

net/websockets/websocket_throttle.cc

Index: net/websockets/websocket_throttle.cc
diff --git a/net/websockets/websocket_throttle.cc b/net/websockets/websocket_throttle.cc
index 2d628151386b4eb67db2f913c73ccb6f6f76a4e8..c714de6bf46a21ced135be98d24409683e90cc4b 100644
--- a/net/websockets/websocket_throttle.cc
+++ b/net/websockets/websocket_throttle.cc
@@ -54,6 +54,11 @@ WebSocketThrottle::~WebSocketThrottle() {
   DCHECK(addr_map_.empty());
 }
 
+// static
+WebSocketThrottle* WebSocketThrottle::GetInstance() {
+  return Singleton<WebSocketThrottle>::get();
+}
+
 void WebSocketThrottle::PutInQueue(WebSocketJob* job) {
   queue_.push_back(job);
   const AddressList& address_list = job->address_list();