Fix DCHECK, memory leak, and refactor PasswordStore to use CancelableRequest

content/browser/cancelable_request.h

 // Copyright (c) 2010 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.
 
 // CancelableRequestProviders and Consumers work together to make requests that
 // execute on a background thread in the provider and return data to the
 // consumer. These class collaborate to keep a list of open requests and to
 // make sure that requests to not outlive either of the objects involved in the
 // transaction.
 //
@@ skipping 109 matching lines @@
 
   CancelableRequestProvider();
   virtual ~CancelableRequestProvider();
 
   // Called by the enduser of the request to cancel it. This MUST be called on
   // the same thread that originally issued the request (which is also the same
   // thread that would have received the callback if it was not canceled).
   // handle must be for a valid pending (not yet complete or cancelled) request.
   void CancelRequest(Handle handle);
 
+  // Provide factory method so Handle can be treated as opaque.
+  static Handle InvalidHandle();
+
+  // Provide validity method so Handle can be treated as opaque.
+  static bool HandleIsValid(Handle handle);
+
  protected:
+  static const Handle kFirstHandle;

[James Hawkins, 2011/03/22 22:59:49]

Can these be private?

[Sheridan Rawlins, 2011/03/23 00:39:52]

Done.

+  static const Handle kInvalidHandle;
+
   // Adds a new request and initializes it. This is called by a derived class
   // to add a new request. The request's Init() will be called (which is why
   // the consumer is required. The handle to the new request is returned.
   Handle AddRequest(CancelableRequestBase* request,
                     CancelableRequestConsumerBase* consumer);
 
   // Called by the CancelableRequest when the request has executed. It will
   // be removed from the list of pending requests (as opposed to canceling,
   // which will also set some state on the request).
   void RequestCompleted(Handle handle);
@@ skipping 554 matching lines @@
   }
 
   // The value.
   Type value;
 
  protected:
   virtual ~CancelableRequest1() {}
 };
 
 #endif  // CONTENT_BROWSER_CANCELABLE_REQUEST_H_