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

net/websockets/websocket_throttle.h

Index: net/websockets/websocket_throttle.h
diff --git a/net/websockets/websocket_throttle.h b/net/websockets/websocket_throttle.h
index 0849834befa1dfaca0e43a97338d49d74e7dea47..9becc62779317ae3e6f7c6e0303dfd134b90485b 100644
--- a/net/websockets/websocket_throttle.h
+++ b/net/websockets/websocket_throttle.h
@@ -10,7 +10,8 @@
 #include <string>
 
 #include "base/hash_tables.h"
-#include "base/singleton.h"
+
+template <typename T> struct DefaultSingletonTraits;
 
 namespace net {
 
@@ -27,6 +28,9 @@ class WebSocketJob;
 //        for that connection to have failed.
 class WebSocketThrottle {
  public:
+  // Returns the singleton instance.
+  static WebSocketThrottle* GetInstance();
+
   // Puts |job| in |queue_| and queues for the destination addresses
   // of |job|.
   // If other job is using the same destination address, set |job| waiting.