Don't use FormFieldData only as a key in a map

components/password_manager/content/browser/content_password_manager_driver.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_CONTENT_BROWSER_CONTENT_PASSWORD_MANAGER_DRIVER_H_
 #define COMPONENTS_PASSWORD_MANAGER_CONTENT_BROWSER_CONTENT_PASSWORD_MANAGER_DRIVER_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "components/password_manager/core/browser/password_autofill_manager.h"
@@ skipping 45 matching lines @@
   bool OnMessageReceived(const IPC::Message& message) override;
   void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) override;
 
  private:
   PasswordManager password_manager_;
   PasswordGenerationManager password_generation_manager_;
   PasswordAutofillManager password_autofill_manager_;
 
+  // Every instance of PasswordFormFillData created by |*this| and sent to
+  // PasswordAutofillManager and PasswordAutofillAgent is given an ID, so that
+  // the latter two classes can reference to the same instance without sending
+  // it to each other over IPC. The counter below is used to generate new IDs.
+  int next_free_key_;
+
   DISALLOW_COPY_AND_ASSIGN(ContentPasswordManagerDriver);
 };
 
 }  // namespace password_manager
 
 #endif  // COMPONENTS_PASSWORD_MANAGER_CONTENT_BROWSER_CONTENT_PASSWORD_MANAGER_DRIVER_H_