feat($ionicActionSheet): add cancelOnStateChange option, default true

Closes #1318

BREAKING CHANGE: $ionicActionSheet's default behavior is now to cancel
when the app's state changes.  To disable this behavior, pass
`cancelOnStateChange: false` into $ionicActionSheet.show().

js/angular/service/actionSheet.js

@@ -82,6 +82,8 @@ function($rootScope, $document, $compile, $animate, $timeout, $ionicTemplateLoad
    *     the action sheet, or false to keep it opened.
    *  - `{function=}` `destructiveButtonClicked` Called when the destructive button is clicked.
    *     Return true to close the action sheet, or false to keep it opened.
+   *  -  `{boolean=}` `cancelOnStateChange` Whether to cancel the actionSheet when navigating
+   *     to a new state.  Default true.
    *
    * @returns {function} `hideSheet` A function which, when called, hides & cancels the action sheet.
    */
@@ -94,14 +96,20 @@ function($rootScope, $document, $compile, $animate, $timeout, $ionicTemplateLoad
       buttonClicked: angular.noop,
       $deregisterBackButton: angular.noop,
       buttons: [],
+      cancelOnStateChange: true
     }, opts || {});
 
+
     // Compile the template
     var element = scope.element = $compile('<ion-action-sheet buttons="buttons"></ion-action-sheet>')(scope);
 
     // Grab the sheet element for animation
     var sheetEl = jqLite(element[0].querySelector('.action-sheet-wrapper'));
 
+    var stateChangeListenDone = scope.cancelOnStateChange ?
+      $rootScope.$on('$stateChangeSuccess', function() { scope.cancel(); }) :
+      angular.noop;
+
     // removes the actionSheet from the screen
     scope.removeSheet = function(done) {
       if (scope.removed) return;
@@ -110,6 +118,8 @@ function($rootScope, $document, $compile, $animate, $timeout, $ionicTemplateLoad
       sheetEl.removeClass('action-sheet-up');
       $document[0].body.classList.remove('action-sheet-open');
       scope.$deregisterBackButton();
+      stateChangeListenDone();
+      scope.cancel.$scope = null; //see last line
 
       $animate.removeClass(element, 'active', function() {
         scope.$destroy();

test/unit/angular/service/actionSheet.unit.js

@@ -84,4 +84,20 @@ describe('Ionic ActionSheet Service', function() {
     expect(cancelSpy).toHaveBeenCalled();
   }));
 
+  it('should cancelOnStateChange by default', inject(function($rootScope) {
+    var scope = setup();
+    spyOn(scope, 'cancel');
+    $rootScope.$broadcast('$stateChangeSuccess');
+    expect(scope.cancel).toHaveBeenCalled();
+  }));
+
+  it('should not cancelOnStateChange with option as false', inject(function($rootScope) {
+    var scope = setup({
+      cancelOnStateChange: false
+    });
+    spyOn(scope, 'cancel');
+    $rootScope.$broadcast('$stateChangeSuccess');
+    expect(scope.cancel).not.toHaveBeenCalled();
+  }));
+
 });