[net] Better StopCaching() handling for HttpCache::Transaction.

net/url_request/url_request.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_URL_REQUEST_URL_REQUEST_H_
 #define NET_URL_REQUEST_URL_REQUEST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 523 matching lines @@
   //
   // If a read error occurs, Read returns false and the request->status
   // will be set to an error.
   bool Read(IOBuffer* buf, int max_bytes, int* bytes_read);
 
   // If this request is being cached by the HTTP cache, stop subsequent caching.
   // Note that this method has no effect on other (simultaneous or not) requests
   // for the same resource. The typical example is a request that results in
   // the data being stored to disk (downloaded instead of rendered) so we don't
   // want to store it twice.
+  //
+  // Should only be called if there are no pending operations.
   void StopCaching();
 
   // This method may be called to follow a redirect that was deferred in
   // response to an OnReceivedRedirect call.
   void FollowDeferredRedirect();
 
   // This method must be called to resume network communications that were
   // deferred in response to an OnBeforeNetworkStart call.
   void ResumeNetworkStart();
 
@@ skipping 274 matching lines @@
   HostPortPair proxy_server_;
 
   scoped_ptr<const base::debug::StackTrace> stack_trace_;
 
   DISALLOW_COPY_AND_ASSIGN(URLRequest);
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_H_