modernize corners & borders in animation demo (#13352)

examples/flutter_gallery/lib/demo/animation/home.dart

@@ -216,12 +216,8 @@ class _AllSectionsLayout extends MultiChildLayoutDelegate {
       final Rect cardRect = _interpolateRect(columnCardRect, rowCardRect).shift(offset);
       final String cardId = 'card$index';
       if (hasChild(cardId)) {
-        // Add a small horizontal gap between the cards.
-        final Rect insetRect = new Rect.fromLTWH(
-          cardRect.left + 0.5, cardRect.top, cardRect.width - 1.0, cardRect.height
-        );
-        layoutChild(cardId, new BoxConstraints.tight(insetRect.size));
-        positionChild(cardId, insetRect.topLeft);
+        layoutChild(cardId, new BoxConstraints.tight(cardRect.size));
+        positionChild(cardId, cardRect.topLeft);
       }
 
       // Layout the title for index.
@@ -549,7 +545,7 @@ class _AnimationDemoHomeState extends State<AnimationDemoHome> {
     final double screenHeight = mediaQueryData.size.height;
     final double appBarMaxHeight = screenHeight - statusBarHeight;
 
-    // The scrolloffset that reveals the appBarMidHeight appbar.
+    // The scroll offset that reveals the appBarMidHeight appbar.
     final double appBarMidScrollOffset = statusBarHeight + appBarMaxHeight - _kAppBarMidHeight;
 
     return new SizedBox.expand(

examples/flutter_gallery/lib/demo/animation/widgets.dart

@@ -19,28 +19,24 @@ class SectionCard extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return new Padding(
-      padding: const EdgeInsets.only(bottom: 1.0),
-      child: new DecoratedBox(
-        decoration: new BoxDecoration(
-          borderRadius: new BorderRadius.circular(4.0),
-          gradient: new LinearGradient(
-            begin: Alignment.centerLeft,
-            end: Alignment.centerRight,
-            colors: <Color>[
-              section.leftColor,
-              section.rightColor,
-            ],
-          ),
-        ),
-        child: new Image.asset(
-          section.backgroundAsset,
-          package: section.backgroundAssetPackage,
-          color: const Color.fromRGBO(255, 255, 255, 0.075),
-          colorBlendMode: BlendMode.modulate,
-          fit: BoxFit.cover,
+    return new DecoratedBox(
+      decoration: new BoxDecoration(
+        gradient: new LinearGradient(
+          begin: Alignment.centerLeft,
+          end: Alignment.centerRight,
+          colors: <Color>[
+            section.leftColor,
+            section.rightColor,
+          ],
         ),
       ),
+      child: new Image.asset(
+        section.backgroundAsset,
+        package: section.backgroundAssetPackage,
+        color: const Color.fromRGBO(255, 255, 255, 0.075),
+        colorBlendMode: BlendMode.modulate,
+        fit: BoxFit.cover,
+      ),
     );
   }
 }