Pin keyboard improvements.

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

Index: chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.html
diff --git a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.html b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.html
index f5cbab20d0af579d3067bc6532916bef3660da77..09e4fed130c856e1c4bdc40b5a7391fd96dee61d 100644
--- a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.html
+++ b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.html
@@ -220,7 +220,10 @@
           </paper-button>
           <paper-icon-button class="digit-button backspace-button"
                              disabled="[[!hasInput_(value)]]"
-                             on-tap="onPinClear_" icon="pin-keyboard:backspace">
+                             icon="pin-keyboard:backspace"
+                             on-mousedown="onBackspaceMouseDown_"
+                             on-mouseleave="onBackspaceMouseUpLeave_"
+                             on-mouseup="onBackspaceMouseUpLeave_">
           </paper-icon-button>
         </div>
       </div>