Add a basic functionality to the force-saving menu item.

components/autofill/content/common/autofill_messages.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.
 
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
 #include "base/strings/string16.h"
@@ skipping 169 matching lines @@
 IPC_MESSAGE_ROUTED2(AutofillMsg_FillPasswordSuggestion,
                     base::string16 /* username */,
                     base::string16 /* password */)
 
 // Tells the renderer to preview the username and password with the given
 // values.
 IPC_MESSAGE_ROUTED2(AutofillMsg_PreviewPasswordSuggestion,
                     base::string16 /* username */,
                     base::string16 /* password */)
 
+// Tells the renderer to find the focused password form (assuming it exists).
+// Renderer is expected to respond with the message
+// |AutofillHostMsg_FocusedPasswordFormFound|.
+IPC_MESSAGE_ROUTED0(AutofillMsg_FindFocusedPasswordForm)
+
 // Tells the renderer that this password form is not blacklisted.  A form can
 // be blacklisted if a user chooses "never save passwords for this site".
 IPC_MESSAGE_ROUTED1(AutofillMsg_FormNotBlacklisted,
                     autofill::PasswordForm /* form checked */)
 
 // Sent when requestAutocomplete() finishes (either succesfully or with an
 // error). If it was a success, the renderer fills the form that requested
 // autocomplete with the |form_data| values input by the user. |message|
 // is printed to the console if non-empty.
 IPC_MESSAGE_ROUTED3(AutofillMsg_RequestAutocompleteResult,
@@ skipping 131 matching lines @@
     int /* key */,
     base::i18n::TextDirection /* text_direction */,
     base::string16 /* username typed by user */,
     int /* options bitmask of autofill::ShowPasswordSuggestionsOptions */,
     gfx::RectF /* input field bounds, window-relative */)
 
 // Inform browser of data list values for the curent field.
 IPC_MESSAGE_ROUTED2(AutofillHostMsg_SetDataList,
                     std::vector<base::string16> /* values */,
                     std::vector<base::string16> /* labels */)
+
+// Inform the browser which password form is currently focused.

[Mike West, 2015/05/29 07:24:49]

What does it return if there is not a password form currently focused?

[msramek, 2015/05/29 11:57:21]

My original intention was that if there is no form, this message would never be
sent (thus, ContentPasswordManagerDriver would never get the response, and so
nothing would happen).

However, it might be helpful to return an empty |autofill::PasswordForm|. The
password manager will be able to handle this as an error and show an error
message in the bubble. How exactly this would work is still up to discussion
with UI, but since the user made an explicit action, we shouldn't just fail
silently.

+IPC_MESSAGE_ROUTED1(AutofillHostMsg_FocusedPasswordFormFound,
+                    autofill::PasswordForm)