Fix gallery clipping issues on ipod touch. (#5258)

* Shrine tile height now hardcoded to match actual card size.
* Animation demo now scales with screen size.

BUG=https://github.com/flutter/flutter/issues/5002
BUG=https://github.com/flutter/flutter/issues/5003

examples/flutter_gallery/lib/demo/animation_demo.dart

@@ -115,12 +115,15 @@ class _PointDemoState extends State<_PointDemo> {
 
   CurvedAnimation _animation;
   _DragTarget _dragTarget;
-  Point _begin = const Point(180.0, 110.0);
-  Point _end = const Point(37.0, 250.0);
+  Point _begin;
+  Point _end;
 
   @override
   void initState() {
     super.initState();
+    final Size screenSize = MediaQuery.of(context).size;
+    _begin = new Point(screenSize.width * 0.5, screenSize.height * 0.2);
+    _end = new Point(screenSize.width * 0.1, screenSize.height * 0.4);
     _animation = new CurvedAnimation(parent: config.controller, curve: Curves.ease);
   }
 
@@ -272,12 +275,21 @@ class _RectangleDemoState extends State<_RectangleDemo> {
 
   CurvedAnimation _animation;
   _DragTarget _dragTarget;
-  Rect _begin = new Rect.fromLTRB(180.0, 100.0, 330.0, 200.0);
-  Rect _end = new Rect.fromLTRB(32.0, 275.0, 132.0, 425.0);
+  Rect _begin;
+  Rect _end;
 
   @override
   void initState() {
     super.initState();
+    final Size screenSize = MediaQuery.of(context).size;
+    _begin = new Rect.fromLTWH(
+      screenSize.width * 0.5, screenSize.height * 0.2,
+      screenSize.width * 0.4, screenSize.height * 0.2
+    );
+    _end = new Rect.fromLTWH(
+      screenSize.width * 0.1, screenSize.height * 0.4,
+      screenSize.width * 0.3, screenSize.height * 0.3
+    );
     _animation = new CurvedAnimation(parent: config.controller, curve: Curves.ease);
   }
 

examples/flutter_gallery/lib/demo/shrine/shrine_home.dart

@@ -39,7 +39,8 @@ class ShrineGridDelegate extends GridDelegate {
     assert(childCount >= 0);
     return new GridSpecification.fromRegularTiles(
       tileWidth: constraints.maxWidth / 2.0 - 8.0,
-      tileHeight: constraints.maxWidth * 0.67,
+      // height = ProductPriceItem + product image + VendorItem
+      tileHeight: 40.0 + 144.0 + 40.0,
       columnCount: 2,
       rowCount: childCount == 0 ? 0 : _rowAtIndex(childCount - 1) + 1,
       rowSpacing: 8.0,