Password autofill should not override explicitly typed password

components/autofill/content/renderer/password_autofill_agent.h

 // Copyright 2013 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_AUTOFILL_CONTENT_RENDERER_PASSWORD_AUTOFILL_AGENT_H_
 #define COMPONENTS_AUTOFILL_CONTENT_RENDERER_PASSWORD_AUTOFILL_AGENT_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 76 matching lines @@
   // Ways to restrict which passwords are saved in ProvisionallySavePassword.
   enum ProvisionallySaveRestriction {
     RESTRICTION_NONE,
     RESTRICTION_NON_EMPTY_PASSWORD
   };
 
   struct PasswordInfo {
     blink::WebInputElement password_field;
     PasswordFormFillData fill_data;
     bool backspace_pressed_last;
-    PasswordInfo() : backspace_pressed_last(false) {}
+    // "Wait for username change" before overwriting the password value -- if
+    // set to true, this flag means that after selecting a username for password
+    // autofill, the user overwrote the autofileld password. The agent should
+    // not restore it back to the autofilled password, so it holds on with
+    // changing the password value until the flag is reset. The flag is reset
+    // when the user chooses another username for autofill.
+    bool wait_for_username_change;

[engedy, 2014/08/06 10:18:17]

To be consistent with |backspace_pressed_last|, I would name this flag from the
"what happened" side and say |password_was_edited_last|.

I would also shorten the comment like:

  // The most recent <<insert antonym for NOOP her>> interaction with the form
was the user manually editing the password value.

[vabr (Chromium), 2014/08/25 14:53:29]

Done.
That's not entirely true if the form has more editable fields than the username
and password. So I reformulated your suggestion a little.

+    PasswordInfo();
   };
   typedef std::map<blink::WebElement, PasswordInfo> LoginToPasswordInfoMap;
+  typedef std::map<blink::WebElement, blink::WebElement> PasswordToLoginMap;
   typedef std::map<blink::WebFrame*,
                    linked_ptr<PasswordForm> > FrameToPasswordFormMap;
 
-  // This class holds a vector of autofilled password input elements and makes
-  // sure the autofilled password value is not accessible to JavaScript code
-  // until the user interacts with the page.
+  // This class keeps track of autofilled password input elements and makes sure
+  // the autofilled password value is not accessible to JavaScript code until
+  // the user interacts with the page.
   class PasswordValueGatekeeper {
    public:
     PasswordValueGatekeeper();
     ~PasswordValueGatekeeper();
 
     // Call this for every autofilled password field, so that the gatekeeper
     // protects the value accordingly.
     void RegisterElement(blink::WebInputElement* element);
 
     // Call this to notify the gatekeeper that the user interacted with the
@@ skipping 67 matching lines @@
       const blink::WebInputElement& password,
       const PasswordFormFillData& fill_data);
 
   // Invoked when the passed frame is closing.  Gives us a chance to clear any
   // reference we may have to elements in that frame.
   void FrameClosing(const blink::WebFrame* frame);
 
   // Finds login information for a |node| that was previously filled.
   bool FindLoginInfo(const blink::WebNode& node,
                      blink::WebInputElement* found_input,
-                     PasswordInfo* found_password);
+                     PasswordInfo** found_password);
 
   // Clears the preview for the username and password fields, restoring both to
   // their previous filled state.
   void ClearPreview(blink::WebInputElement* username,
                     blink::WebInputElement* password);
 
   // If |provisionally_saved_forms_| contains a form for |current_frame| or its
   // children, return such frame.
   blink::WebFrame* CurrentOrChildFrameWithSavedForms(
       const blink::WebFrame* current_frame);
 
   // Extracts a PasswordForm from |form| and saves it as
   // |provisionally_saved_forms_[frame]|, as long as it satisfies |restriction|.
   void ProvisionallySavePassword(blink::WebLocalFrame* frame,
                                  const blink::WebFormElement& form,
                                  ProvisionallySaveRestriction restriction);
 
   // The logins we have filled so far with their associated info.
   LoginToPasswordInfoMap login_to_password_info_;
+  // Maps password elements to the corresponding username elements, good for

[engedy, 2014/08/06 10:18:17]

nit: I would personally also consider shortening or dropping this comment.

[vabr (Chromium), 2014/08/25 14:53:29]

Done.

+  // looking up PasswordInfo associated with a password element in
+  // |login_to_password_info_|.
+  PasswordToLoginMap password_to_username_;
 
   // Used for UMA stats.
   OtherPossibleUsernamesUsage usernames_usage_;
 
   // Pointer to the WebView. Used to access page scale factor.
   blink::WebView* web_view_;
 
   // Set if the user might be submitting a password form on the current page,
   // but the submit may still fail (i.e. doesn't pass JavaScript validation).
   FrameToPasswordFormMap provisionally_saved_forms_;
@@ skipping 16 matching lines @@
   bool did_stop_loading_;
 
   base::WeakPtrFactory<PasswordAutofillAgent> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PasswordAutofillAgent);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CONTENT_RENDERER_PASSWORD_AUTOFILL_AGENT_H_