Fix more analyzer warnings

packages/flutter/example/widgets/card_collection.dart

@@ -45,7 +45,7 @@ class ShrinkingCard extends AnimatedComponent {
   Function onUpdated;
   Function onCompleted;
 
-  double get currentHeight => (card.performance.variable as AnimatedType).value;
+  double get currentHeight => (card.performance.variable as AnimatedValue).value;
 
   void initState() {
     assert(card.performance != null);

packages/flutter/lib/rendering/flex.dart

@@ -93,6 +93,7 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
     }
   }
 
+  double _overflow;
 
   void setupParentData(RenderBox child) {
     if (child.parentData is! FlexBoxParentData)