fix(input): update $viewValue when cleared

- Fix when user clicks clear button in an input element in IE, $viewValue not being correctly updated

Author: wesleycho

src/ng/directive/input.js

@@ -1126,7 +1126,7 @@ function baseInputType(scope, element, attr, ctrl, $sniffer, $browser) {
     });
   }
 
-  var timeout;
+  var timeout, oldVal;
 
   var listener = function(ev) {
     if (timeout) {
@@ -1152,10 +1152,17 @@ function baseInputType(scope, element, attr, ctrl, $sniffer, $browser) {
     }
   };
 
+  function ieListener(ev) {
+    var val = element.val();
+    if (val === oldVal) return;
+    oldVal = val;
+    listener(ev);
+  }
+
   // if the browser does support "input" event, we are fine - except on IE9 which doesn't fire the
   // input event on backspace, delete or cut
   if ($sniffer.hasEvent('input')) {
-    element.on('input', listener);
+    element.on('input', msie ? ieListener : listener);
   } else {
     var deferListener = function(ev, input, origValue) {
       if (!timeout) {