Adding histograms showing fraction of page load times

net/base/network_delegate.h

 // Copyright (c) 2012 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_BASE_NETWORK_DELEGATE_H_
 #define NET_BASE_NETWORK_DELEGATE_H_
 #pragma once
 
 #include <string>
 
@@ skipping 31 matching lines @@
   // OnAuthRequired call. It's placed in this file to prevent url_request.h
   // from having to include network_delegate.h.
   enum AuthRequiredResponse {
     AUTH_REQUIRED_RESPONSE_NO_ACTION,
     AUTH_REQUIRED_RESPONSE_SET_AUTH,
     AUTH_REQUIRED_RESPONSE_CANCEL_AUTH,
     AUTH_REQUIRED_RESPONSE_IO_PENDING,
   };
   typedef base::Callback<void(AuthRequiredResponse)> AuthCallback;
 
+  enum CacheWaitState {
+    CACHE_WAIT_STATE_START,
+    CACHE_WAIT_STATE_FINISH,
+    CACHE_WAIT_STATE_DONE
+  };
+
   virtual ~NetworkDelegate() {}
 
   // Notification interface called by the network stack. Note that these
   // functions mostly forward to the private virtuals. They also add some sanity
   // checking on parameters. See the corresponding virtuals for explanations of
   // the methods and their arguments.
   int NotifyBeforeURLRequest(URLRequest* request,
                              const CompletionCallback& callback,
                              GURL* new_url);
   int NotifyBeforeSendHeaders(URLRequest* request,
@@ skipping 22 matching lines @@
   bool CanSetCookie(const URLRequest& request,
                     const std::string& cookie_line,
                     CookieOptions* options);
   bool CanAccessFile(const URLRequest& request,
                      const FilePath& path) const;
   bool CanThrottleRequest(const URLRequest& request) const;
 
   int NotifyBeforeSocketStreamConnect(SocketStream* socket,
                                       const CompletionCallback& callback);
 
+  void NotifyCacheWaitStateChange(const URLRequest& request,
+                                  CacheWaitState state);
+
  private:
   // This is the interface for subclasses of NetworkDelegate to implement. These
   // member functions will be called by the respective public notification
   // member function, which will perform basic sanity checking.
 
   // Called before a request is sent. Allows the delegate to rewrite the URL
   // being fetched by modifying |new_url|. |callback| and |new_url| are valid
   // only until OnURLRequestDestroyed is called for this request. Returns a net
   // status code, generally either OK to continue with the request or
   // ERR_IO_PENDING if the result is not ready yet. A status code other than OK
@@ skipping 104 matching lines @@
                                const FilePath& path) const = 0;
 
   // Returns true if the given request may be rejected when the
   // URLRequestThrottlerManager believes the server servicing the
   // request is overloaded or down.
   virtual bool OnCanThrottleRequest(const URLRequest& request) const = 0;
 
   // Called before a SocketStream tries to connect.
   virtual int OnBeforeSocketStreamConnect(
       SocketStream* socket, const CompletionCallback& callback) = 0;
+
+  // Called when the completion of a URLRequest is blocking on a cache
+  // transaction (CACHE_WAIT_STATE_START), or when a URLRequest is no longer
+  // blocked on a cache transaction (CACHE_WAIT_STATE_FINISH), or when a
+  // URLRequest is completely done (CACHE_WAIT_STATE_DONE), indicating
+  // cancellation of any pending cache waits for this request.  Notice that
+  // START called several times for the same request.  It is the responsibility
+  // of the delegate to keep track of the number of outstanding cache
+  // transactions.
+  virtual void OnCacheWaitStateChange(const URLRequest& request,
+                                      CacheWaitState state) = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_DELEGATE_H_