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

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

Index: chrome/browser/resources/settings/people_page/fingerprint_list.js
diff --git a/chrome/browser/resources/settings/people_page/fingerprint_list.js b/chrome/browser/resources/settings/people_page/fingerprint_list.js
index d6c142e086815f5ec6904485d1999fbc3ebaf9be..1cb0239a67dc07754da3f7968362e3687515466f 100644
--- a/chrome/browser/resources/settings/people_page/fingerprint_list.js
+++ b/chrome/browser/resources/settings/people_page/fingerprint_list.js
@@ -126,10 +126,10 @@ Polymer({
    * @private
    */
   onFingerprintDeleteTapped_: function(e) {
-    this.browserProxy_.removeEnrollment(e.model.index).then(function(success) {
+    this.browserProxy_.removeEnrollment(e.model.index).then(success => {
       if (success)
         this.updateFingerprintsList_();
-    }.bind(this));
+    });
   },
 
   /**
@@ -138,10 +138,10 @@ Polymer({
    */
   onFingerprintLabelChanged_: function(e) {
     this.browserProxy_.changeEnrollmentLabel(e.model.index, e.model.item)
-        .then(function(success) {
+        .then(success => {
           if (success)
             this.updateFingerprintsList_();
-        }.bind(this));
+        });
   },
 
   /**