MD Settings: Convert all usages of .bind(this) to use ES6 arrow function.

chrome/browser/resources/settings/people_page/password_prompt_dialog.js

 // Copyright 2016 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
  *
  * 'settings-password-prompt-dialog' shows a dialog which asks for the user to
  * enter their password. It validates the password is correct. Once the user has
  * entered their account password, the page fires an 'authenticated' event and
@@ skipping 81 matching lines @@
     passwordActiveDurationMs_: {
       type: Number,
       value: PASSWORD_ACTIVE_DURATION_MS,
     },
   },
 
   /** @override */
   attached: function() {
     this.writeUma_(LockScreenProgress.START_SCREEN_LOCK);
     this.$.dialog.showModal();
-    this.async(function() {
+    this.async(() => {
       this.$.passwordInput.focus();
-    }.bind(this));
+    });
   },
 
   /** @private */
   onCancelTap_: function() {
     if (this.$.dialog.open)
       this.$.dialog.close();
   },
 
   /**
    * Called whenever the dialog is closed.
@@ skipping 21 matching lines @@
       // The password might have been cleared during the duration of the
       // getActiveModes call.
       this.passwordInvalid_ = !valid && !!this.password_;
 
       if (valid) {
         // Create the |this.setModes| closure and automatically clear it after
         // |this.passwordActiveDurationMs_|.
         var password = this.password_;
         this.password_ = '';
 
-        this.setModes = function(modes, credentials, onComplete) {
+        this.setModes = (modes, credentials, onComplete) => {
           this.quickUnlockPrivate_.setModes(
               password, modes, credentials, onComplete);
-        }.bind(this);
+        };
 
         function clearSetModes() {
           // Reset the password so that any cached references to this.setModes
           // will fail.
           password = '';
           this.setModes = null;
         }
 
         this.clearAccountPasswordTimeout_ = setTimeout(
             clearSetModes.bind(this), this.passwordActiveDurationMs_);
@@ skipping 20 matching lines @@
     return !!this.password_ && !this.passwordInvalid_;
   },
 
   /**
    * Helper method that checks if the current password is valid.
    * @param {function(boolean):void} onCheck
    */
   checkAccountPassword_: function(onCheck) {
     // We check the account password by trying to update the active set of quick
     // unlock modes without changing any credentials.
-    this.quickUnlockPrivate_.getActiveModes(function(modes) {
+    this.quickUnlockPrivate_.getActiveModes(modes => {
       var credentials =
           /** @type {!Array<string>} */ (Array(modes.length).fill(''));
       this.quickUnlockPrivate_.setModes(
           this.password_, modes, credentials, onCheck);
-    }.bind(this));
+    });
   }
 });
 
 })();