Changed look of pin keyboard.

chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js

Index: chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
diff --git a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
index a5cbe3b7c5c1c5616a7a1ababb4cc36f279640c4..7ce2b3c01566fcf091ee19f5f59f18c3bc5235ec 100644
--- a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
+++ b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
@@ -14,6 +14,20 @@ Polymer({
     input.value += value;
   },
 
+  // Called when the user wants to clear the current entered PIN value.
+  onPinClear_: function() {
+    var pin = this.$$('#pin-input');
+    switch (pin.value.length) {
+      case 0:
+      case 1:
+        pin.value = '';

[jdufault, 2016/06/22 18:03:44]

Does this need to be special cased?

  ''.substring(0, -1) evals to ''

[sammiequon, 2016/06/22 23:05:40]

Done.

+        break;
+      default:
+        pin.value = pin.value.substring(0, pin.value.length - 1);
+        break;
+    }
+  },
+
   // Called when the user wants to submit the PIN.
   onPinSubmit_: function() {
     var pin = this.$$('#pin-input').value;