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

chrome/browser/password_manager/password_store_consumer.h

+// Copyright (c) 2011 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 CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_CONSUMER_H_
+#define CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_CONSUMER_H_
+#pragma once
+
+#include "content/browser/cancelable_request.h"
+
+namespace webkit_glue {
+struct PasswordForm;
+};
+
+// Reads from the PasswordStore are done asynchrously on a separate
+// thread. PasswordStoreConsumer provides the virtual callback method, which is
+// guaranteed to be executed on this (the UI) thread. It also provides the
+// CancelableRequestConsumer member, which cancels any outstanding requests upon
+// destruction.
+class PasswordStoreConsumer {
+ public:
+  // Call this when the request is finished. If there are no results, call it
+  // anyway with an empty vector.
+  virtual void OnPasswordStoreRequestDone(
+      CancelableRequestProvider::Handle handle,
+      const std::vector<webkit_glue::PasswordForm*>& result) = 0;
+
+  // The CancelableRequest framework needs both a callback (the
+  // PasswordStoreConsumer::OnPasswordStoreRequestDone) as well as a
+  // CancelableRequestConsumer.  This accessor makes the API simpler for callers
+  // as PasswordStore can get both from the PasswordStoreConsumer.
+  CancelableRequestConsumerBase* cancelable_consumer() {
+    return &cancelable_consumer_;
+  }
+
+ protected:
+  virtual ~PasswordStoreConsumer();
+
+ private:
+  CancelableRequestConsumer cancelable_consumer_;
+};
+
+#endif  // CHROME_BROWSER_PASSWORD_MANAGER_PASSWORD_STORE_CONSUMER_H_