GetLoginsRequest: Use ScopedVector to express ownership of forms

components/password_manager/core/browser/password_store_consumer.h

 // Copyright 2014 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 COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_PASSWORD_STORE_CONSUMER_H_
 #define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_PASSWORD_STORE_CONSUMER_H_
 
 #include <vector>
 
+#include "base/memory/scoped_vector.h"
 #include "base/task/cancelable_task_tracker.h"
 
 namespace autofill {
 struct PasswordForm;
 }
 
 namespace password_manager {
 
 // Reads from the PasswordStore are done asynchronously 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
 // base::CancelableTaskTracker member, which cancels any outstanding
 // tasks upon destruction.
 class PasswordStoreConsumer {
  public:
   PasswordStoreConsumer();
 
-  // Called when the request is finished. If there are no results, it is called
-  // with an empty vector.
-  // Note: The implementation owns all PasswordForms in the vector.
-  virtual void OnGetPasswordStoreResults(
-      const std::vector<autofill::PasswordForm*>& results) = 0;
+  // Called when the request is finished. The associated results are accessible
+  // through results().
+  virtual void OnGetPasswordStoreResults() = 0;

[vasilii, 2015/02/03 19:22:17]

This is my deepest concern in the CL. I didn't see places except some tests
where the consumer's benefited from having the member variable. On the other
hand, I did see places where it can bite us:
PasswordFormManager once calls OnGetPasswordStoreResults() hoping that results_
is empty.
PasswordFormManagerTest entirely relies on the fact that
OnGetPasswordStoreResults() will clean result().
CredentialManagerDispatcher may leave some trash in result_.

[vabr (Chromium), 2015/02/04 16:13:44]

Thanks for pointing that out. I agree, and I'm actually not sure why I separated
result from the On* method.
Joined them again.
Done.

 
   // The base::CancelableTaskTracker can be used for cancelling the
   // tasks associated with the consumer.
   base::CancelableTaskTracker* cancelable_task_tracker() {
     return &cancelable_task_tracker_;
   }
 
   base::WeakPtr<PasswordStoreConsumer> GetWeakPtr() {
     return weak_ptr_factory_.GetWeakPtr();
   }
 
+  ScopedVector<autofill::PasswordForm>* results() { return &results_; }
+
  protected:
   virtual ~PasswordStoreConsumer();
 
  private:
+  ScopedVector<autofill::PasswordForm> results_;
   base::CancelableTaskTracker cancelable_task_tracker_;
   base::WeakPtrFactory<PasswordStoreConsumer> weak_ptr_factory_;
 };
 
 }  // namespace password_manager
 
 #endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_PASSWORD_STORE_CONSUMER_H_