fix(scroll): ensure scrollView objects exist

Check if scrollView is null when switching off of tabs view. #2181

Author: adamdbradley

Diff for: js/angular/controller/scrollController.js

@@ -114,7 +114,7 @@ function($scope, scrollViewOptions, $timeout, $window, $$scrollValueCache, $loca
   });
 
   $timeout(function() {
-    scrollView.run();
+    scrollView && scrollView.run && scrollView.run();
   });
 
   this._rememberScrollId = null;
@@ -129,7 +129,7 @@ function($scope, scrollViewOptions, $timeout, $window, $$scrollValueCache, $loca
 
   this.resize = function() {
     return $timeout(resize).then(function() {
-      $element.triggerHandler('scroll.resize');
+      $element && $element.triggerHandler('scroll.resize');
     });
   };
 
@@ -204,7 +204,7 @@ function($scope, scrollViewOptions, $timeout, $window, $$scrollValueCache, $loca
     var values = $$scrollValueCache[this._rememberScrollId];
     if (values) {
       this.resize().then(function() {
-        scrollView.scrollTo(+values.left, +values.top, shouldAnimate);
+        scrollView && scrollView.scrollTo && scrollView.scrollTo(+values.left, +values.top, shouldAnimate);
       });
     }
   };

Diff for: js/views/scrollView.js

@@ -1114,6 +1114,8 @@ ionic.views.Scroll = ionic.views.View.inherit({
   },
 
   resize: function() {
+    if(!this.__container || !this.options) return;
+
     // Update Scroller dimensions for changed content
     // Add padding to bottom of content
     this.setDimensions(