Add "previewing on hover" support for password field.

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 133 matching lines @@
 // generated password.
 IPC_MESSAGE_ROUTED1(AutofillMsg_GeneratedPasswordAccepted,
                     base::string16 /* generated_password */)
 
 // Tells the renderer that the user accepted a password autofill suggestion,
 // and that renderer should set the username and password to the given values.
 IPC_MESSAGE_ROUTED2(AutofillMsg_AcceptPasswordAutofillSuggestion,
                     base::string16 /* username */,
                     base::string16 /* password */)
 
+// Tells the renderer to preview the username and password with the given
+// values.
+IPC_MESSAGE_ROUTED2(AutofillMsg_PreviewPasswordAutofillSuggestion,
+                    base::string16 /* username */,
+                    base::string16 /* password */)
+
 // 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 108 matching lines @@
 IPC_MESSAGE_ROUTED4(AutofillHostMsg_ShowPasswordSuggestions,
                     autofill::FormFieldData /* the form field */,
                     gfx::RectF /* input field bounds, window-relative */,
                     std::vector<base::string16> /* suggestions */,
                     std::vector<base::string16> /* realms */)
 
 // 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 */)