Server push cancellation: add NetLogs to track cache lookup transaction

net/spdy/server_push_delegate.h

 // Copyright (c) 2016 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_SPDY_SERVER_PUSH_DELEGATE_H_
 #define NET_SPDY_SERVER_PUSH_DELEGATE_H_
 
 #include "net/base/net_export.h"
+#include "net/log/net_log_with_source.h"
 #include "url/gurl.h"
 
 namespace net {
 
 // An interface to a class that should be notified when session receives server
 // push.
 class NET_EXPORT_PRIVATE ServerPushDelegate {
  public:
   // An interface to a class that reflects information on the pushed request.
   class NET_EXPORT ServerPushHelper {
    public:
     virtual ~ServerPushHelper() {}
 
     // Cancels the push if it is not claimed yet.
     virtual void Cancel() = 0;
 
     // Gets the URL of the pushed request.
-    virtual const GURL& GetURL() = 0;
+    virtual const GURL& GetURL() const = 0;
   };
 
   virtual ~ServerPushDelegate() {}
 
   // Invoked by session when a push promise has been received.
-  virtual void OnPush(std::unique_ptr<ServerPushHelper> push_helper) = 0;
+  virtual void OnPush(std::unique_ptr<ServerPushHelper> push_helper,
+                      const NetLogWithSource& session_net_log) = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SERVER_PUSH_DELEGATE_H_