perf(ngModel): move model -> view pipeline to watch action

Author: Narretz

src/ng/directive/ngModel.js

@@ -892,13 +892,16 @@ function setupModelWatcher(ctrl) {
   // 4. view should be changed back to 'a'
   ctrl.$$scope.$watch(function ngModelWatch(scope) {
     var modelValue = ctrl.$$ngModelGet(scope);
+    return modelValue;
+  }, ngModelWatchAction);
 
+  function ngModelWatchAction(modelValue) {
     // if scope model value and ngModel value are out of sync
     // TODO(perf): why not move this to the action fn?
     if (modelValue !== ctrl.$modelValue &&
-       // checks for NaN is needed to allow setting the model to NaN when there's an asyncValidator
-        // eslint-disable-next-line no-self-compare
-       (ctrl.$modelValue === ctrl.$modelValue || modelValue === modelValue)
+     // checks for NaN is needed to allow setting the model to NaN when there's an asyncValidator
+      // eslint-disable-next-line no-self-compare
+     (ctrl.$modelValue === ctrl.$modelValue || modelValue === modelValue)
     ) {
       ctrl.$modelValue = ctrl.$$rawModelValue = modelValue;
       ctrl.$$parserValid = undefined;
@@ -921,7 +924,8 @@ function setupModelWatcher(ctrl) {
     }
 
     return modelValue;
-  });
+  }
+
 }
 
 /**