feat($compile): backport $doCheck

Backuport ngDoCheck from Angular 2.

Author: zbjornson

src/ng/compile.js

@@ -300,9 +300,12 @@
  *   `changesObj` is a hash whose keys are the names of the bound properties that have changed, and the values are an
  *   object of the form `{ currentValue, previousValue, isFirstChange() }`. Use this hook to trigger updates within a
  *   component such as cloning the bound value to prevent accidental mutation of the outer value.
- * * `$doCheck()` - Called on each digest cycle. Provides an opportunity to detect and act on
+ * * `$doCheck()` - Called on each turn of the digest cycle. Provides an opportunity to detect and act on
  *   changes. Any actions that you wish to take in response to the changes that you detect must be
- *   invoked from this hook; implementing this has no effect on when `$onChanges` is called.
+ *   invoked from this hook; implementing this has no effect on when `$onChanges` is called. For example, this hook
+ *   could be useful if you wish to perform a deep equality check, or to check a Date object, changes to which would not
+ *   be detected by Angular's change detector and thus not trigger `$onChanges`. This hook is invoked with no arguments;
+ *   if detecting changes, you must store the previous value(s) for comparison to the current values.
  * * `$onDestroy()` - Called on a controller when its containing scope is destroyed. Use this hook for releasing
  *   external resources, watches and event handlers. Note that components have their `$onDestroy()` hooks called in
  *   the same order as the `$scope.$broadcast` events are triggered, which is top down. This means that parent
@@ -2505,6 +2508,9 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
           if (isFunction(controllerInstance.$doCheck)) {
             controllerInstance.$doCheck();
           }
+          if (isFunction(controllerInstance.$doCheck)) {
+            controllerInstance.$doCheck();
+          }
           if (isFunction(controllerInstance.$onDestroy)) {
             controllerScope.$on('$destroy', function callOnDestroyHook() {
               controllerInstance.$onDestroy();