Fix end_to_end_test performance regression caused by using mutexes

net/tools/quic/test_tools/server_thread.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_TOOLS_QUIC_SERVER_THREAD_H_
 #define NET_TOOLS_QUIC_SERVER_THREAD_H_
 
 #include "base/threading/simple_thread.h"
 #include "net/base/ip_endpoint.h"
 #include "net/quic/quic_config.h"
 #include "net/tools/quic/quic_server.h"
 
 namespace net {
 namespace tools {
 namespace test {
 
 // Simple wrapper class to run server in a thread.
 class ServerThread : public base::SimpleThread {
  public:
   ServerThread(IPEndPoint address,
                const QuicConfig& config,
                const QuicVersionVector& supported_versions,
                bool strike_register_no_startup_period);
 
   virtual ~ServerThread();
 
-  // SimpleThread implementation.
+  // Prepares the server, but does not start accepting connections. Useful for
+  // injecting mocks.
+  void Initialize();
+
+  // Runs the event loop. Will initialize if necessary.
   virtual void Run() OVERRIDE;
 
-  // Waits until the server has started and is listening for requests.
-  void WaitForServerStartup();
-
   // Waits for the handshake to be confirmed for the first session created.
   void WaitForCryptoHandshakeConfirmed();
 
-  // Pauses execution of the server until Resume() is called.
+  // Pauses execution of the server until Resume() is called.  May only be
+  // called once.
   void Pause();
 
-  // Resumes execution of the server after Pause() has been called.
+  // Resumes execution of the server after Pause() has been called.  May only
+  // be called once.
   void Resume();
 
   // Stops the server from executing and shuts it down, destroying all
   // server objects.
   void Quit();
 
   // Returns the underlying server.  Care must be taken to avoid data races
   // when accessing the server.  It is always safe to access the server
   // after calling Pause() and before calling Resume().
   QuicServer* server() { return &server_; }
 
   // Returns the port that the server is listening on.
   int GetPort();
 
  private:
   void MaybeNotifyOfHandshakeConfirmation();
 
-  base::Lock event_loop_mu_;       // Held when the server is processing events.
-  base::WaitableEvent listening_;  // Notified when the server is listening.
   base::WaitableEvent confirmed_;  // Notified when the first handshake is
                                    // confirmed.
+  base::WaitableEvent pause_;      // Notified when the server should pause.
+  base::WaitableEvent paused_;     // Notitied when the server has paused
+  base::WaitableEvent resume_;     // Notified when the server should resume.
   base::WaitableEvent quit_;       // Notified when the server should quit.
 
   tools::QuicServer server_;
   IPEndPoint address_;
   base::Lock port_lock_;
   int port_;
 
+  bool initialized_;
+
   DISALLOW_COPY_AND_ASSIGN(ServerThread);
 };
 
 }  // namespace test
 }  // namespace tools
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_SERVER_THREAD_H_