[Gallery] Fix directory structure (#312)

gallery/lib/studies/shrine/scrim.dart

@@ -0,0 +1,46 @@
+// Copyright 2019 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+
+class Scrim extends StatelessWidget {
+  const Scrim({this.controller});
+
+  final AnimationController controller;
+
+  @override
+  Widget build(BuildContext context) {
+    final Size deviceSize = MediaQuery.of(context).size;
+    return ExcludeSemantics(
+      child: AnimatedBuilder(
+        animation: controller,
+        builder: (context, child) {
+          final Color color =
+              Color(0xFFF0EA).withOpacity(controller.value * 0.87);
+
+          final Widget scrimRectangle = Container(
+              width: deviceSize.width, height: deviceSize.height, color: color);
+
+          final bool ignorePointer =
+              (controller.status == AnimationStatus.dismissed);
+          final bool tapToRevert =
+              (controller.status == AnimationStatus.completed);
+
+          if (tapToRevert) {
+            return GestureDetector(
+              onTap: () {
+                controller.reverse();
+              },
+              child: scrimRectangle,
+            );
+          } else if (ignorePointer) {
+            return IgnorePointer(child: scrimRectangle);
+          } else {
+            return scrimRectangle;
+          }
+        },
+      ),
+    );
+  }
+}