Track password field id so it can be used to improve uniqueness of passwordId

chrome/browser/resources/gaia_auth/saml_injected.js

 // 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.
 
 /**
  * @fileoverview
  * Script to be injected into SAML provider pages, serving three main purposes:
  * 1. Signal hosting extension that an external page is loaded so that the
  *    UI around it should be changed accordingly;
  * 2. Provide an API via which the SAML provider can pass user credentials to
@@ skipping 125 matching lines @@
      * @param {!HTMLInputElement} passworField The password field to track.
      */
     trackPasswordField: function(passwordField) {
       var existing = this.passwordFields_.filter(function(element) {
         return element === passwordField;
       });
       if (existing.length != 0)
         return;
 
       var index = this.passwordFields_.length;
+      var fieldId = passwordField.id;

[xiyuan, 2016/06/10 17:05:58]

It is possible that the IdP page does not set "id" for the password field. Let's
give it some fall back values, something like,

var fieldId = passwordField.id || passwordField.name || '';

       passwordField.addEventListener(
-          'input', this.onPasswordChanged_.bind(this, index));
+          'input', this.onPasswordChanged_.bind(this, index, fieldId));
       this.passwordFields_.push(passwordField);
       this.passwordValues_.push(passwordField.value);
     },
 
     /**
      * Check if the password field at |index| has changed. If so, sends back
      * the updated value.
      */
-    maybeSendUpdatedPassword: function(index) {
+    maybeSendUpdatedPassword: function(index, fieldId) {
       var newValue = this.passwordFields_[index].value;
       if (newValue == this.passwordValues_[index])
         return;
 
       this.passwordValues_[index] = newValue;
 
-      // Use an invalid char for URL as delimiter to concatenate page url and
-      // password field index to construct a unique ID for the password field.
-      var passwordId = this.pageURL_.split('#')[0].split('?')[0] + '|' + index;
+      // Use an invalid char for URL as delimiter to concatenate page url,
+      // password field index and id to construct a unique ID for the password
+      // field.
+      var passwordId = this.pageURL_.split('#')[0].split('?')[0] +
+          '|' + index + '|' + fieldId;
       this.channel_.send({
         name: 'updatePassword',
         id: passwordId,
         password: newValue
       });
     },
 
     /**
      * Handles 'change' event in the scraped password fields.
      * @param {number} index The index of the password fields in
      *     |passwordFields_|.

[xiyuan, 2016/06/10 17:05:59]

Document fieldId?

      */
-    onPasswordChanged_: function(index) {
-      this.maybeSendUpdatedPassword(index);
+    onPasswordChanged_: function(index, fieldId) {
+      this.maybeSendUpdatedPassword(index, fieldId);
     }
   };
 
   function onGetSAMLFlag(channel, isSAMLPage) {
     if (!isSAMLPage)
       return;
     var pageURL = window.location.href;
 
     channel.send({name: 'pageLoaded', url: pageURL});
 
@@ skipping 15 matching lines @@
   }
 
   var channel = Channel.create();
   channel.connect('injected');
   channel.sendWithCallback({name: 'getSAMLFlag'},
                            onGetSAMLFlag.bind(undefined, channel));
 
   var apiCallForwarder = new APICallForwarder();
   apiCallForwarder.init(channel);
 })();