Adds some Shrine updates from Material team. (#34)

shrine/lib/app.dart

@@ -50,7 +50,8 @@ class _ShrineAppState extends State<ShrineApp>
       home: HomePage(
         backdrop: Backdrop(
           frontLayer: ProductPage(),
-          backLayer: CategoryMenuPage(onCategoryTap: () => _controller.forward()),
+          backLayer:
+              CategoryMenuPage(onCategoryTap: () => _controller.forward()),
           frontTitle: Text('SHRINE'),
           backTitle: Text('MENU'),
           controller: _controller,
@@ -85,6 +86,7 @@ IconThemeData _customIconTheme(IconThemeData original) {
 ThemeData _buildShrineTheme() {
   final ThemeData base = ThemeData.light();
   return base.copyWith(
+    colorScheme: kShrineColorScheme,
     accentColor: kShrineBrown900,
     primaryColor: kShrinePink100,
     buttonColor: kShrinePink100,
@@ -92,9 +94,13 @@ ThemeData _buildShrineTheme() {
     cardColor: kShrineBackgroundWhite,
     textSelectionColor: kShrinePink100,
     errorColor: kShrineErrorRed,
-    buttonTheme: ButtonThemeData(textTheme: ButtonTextTheme.accent),
-    primaryIconTheme: base.iconTheme.copyWith(color: kShrineBrown900),
-    inputDecorationTheme: InputDecorationTheme(border: CutCornersBorder()),
+    buttonTheme: const ButtonThemeData(
+      colorScheme: kShrineColorScheme,
+      textTheme: ButtonTextTheme.normal,
+    ),
+    primaryIconTheme: _customIconTheme(base.iconTheme),
+    inputDecorationTheme:
+        const InputDecorationTheme(border: CutCornersBorder()),
     textTheme: _buildShrineTextTheme(base.textTheme),
     primaryTextTheme: _buildShrineTextTheme(base.primaryTextTheme),
     accentTextTheme: _buildShrineTextTheme(base.accentTextTheme),
@@ -105,9 +111,7 @@ ThemeData _buildShrineTheme() {
 TextTheme _buildShrineTextTheme(TextTheme base) {
   return base
       .copyWith(
-        headline: base.headline.copyWith(
-          fontWeight: FontWeight.w500,
-        ),
+        headline: base.headline.copyWith(fontWeight: FontWeight.w500),
         title: base.title.copyWith(fontSize: 18.0),
         caption: base.caption.copyWith(
           fontWeight: FontWeight.w400,
@@ -128,3 +132,19 @@ TextTheme _buildShrineTextTheme(TextTheme base) {
         bodyColor: kShrineBrown900,
       );
 }
+
+const ColorScheme kShrineColorScheme = ColorScheme(
+  primary: kShrinePink100,
+  primaryVariant: kShrineBrown900,
+  secondary: kShrinePink50,
+  secondaryVariant: kShrineBrown900,
+  surface: kShrineSurfaceWhite,
+  background: kShrineBackgroundWhite,
+  error: kShrineErrorRed,
+  onPrimary: kShrineBrown900,
+  onSecondary: kShrineBrown900,
+  onSurface: kShrineBrown900,
+  onBackground: kShrineBrown900,
+  onError: kShrineSurfaceWhite,
+  brightness: Brightness.light,
+);

shrine/lib/login.dart

@@ -22,33 +22,33 @@ class LoginPage extends StatefulWidget {
 }
 
 class _LoginPageState extends State<LoginPage> {
-  final _usernameController = TextEditingController();
-  final _passwordController = TextEditingController();
+  final TextEditingController _usernameController = TextEditingController();
+  final TextEditingController _passwordController = TextEditingController();
 
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       body: SafeArea(
         child: ListView(
-          padding: EdgeInsets.symmetric(horizontal: 24.0),
+          padding: const EdgeInsets.symmetric(horizontal: 24.0),
           children: <Widget>[
-            SizedBox(height: 80.0),
+            const SizedBox(height: 80.0),
             Column(
               children: <Widget>[
                 Image.asset('assets/diamond.png'),
-                SizedBox(height: 16.0),
+                const SizedBox(height: 16.0),
                 Text(
                   'SHRINE',
                   style: Theme.of(context).textTheme.headline,
                 ),
               ],
             ),
-            SizedBox(height: 120.0),
+            const SizedBox(height: 120.0),
             PrimaryColorOverride(
               color: kShrineBrown900,
               child: TextField(
                 controller: _usernameController,
-                decoration: InputDecoration(
+                decoration: const InputDecoration(
                   labelText: 'Username',
                 ),
               ),
@@ -58,7 +58,7 @@ class _LoginPageState extends State<LoginPage> {
               color: kShrineBrown900,
               child: TextField(
                 controller: _passwordController,
-                decoration: InputDecoration(
+                decoration: const InputDecoration(
                   labelText: 'Password',
                 ),
               ),
@@ -66,8 +66,8 @@ class _LoginPageState extends State<LoginPage> {
             ButtonBar(
               children: <Widget>[
                 FlatButton(
-                  child: Text('CANCEL'),
-                  shape: BeveledRectangleBorder(
+                  child: const Text('CANCEL'),
+                  shape: const BeveledRectangleBorder(
                     borderRadius: BorderRadius.all(Radius.circular(7.0)),
                   ),
                   onPressed: () {
@@ -76,9 +76,9 @@ class _LoginPageState extends State<LoginPage> {
                   },
                 ),
                 RaisedButton(
-                  child: Text('NEXT'),
+                  child: const Text('NEXT'),
                   elevation: 8.0,
-                  shape: BeveledRectangleBorder(
+                  shape: const BeveledRectangleBorder(
                     borderRadius: BorderRadius.all(Radius.circular(7.0)),
                   ),
                   onPressed: () {

shrine/lib/supplemental/cut_corners_border.dart

@@ -19,7 +19,7 @@ import 'package:flutter/widgets.dart';
 
 class CutCornersBorder extends OutlineInputBorder {
   const CutCornersBorder({
-    BorderSide borderSide: BorderSide.none,
+    BorderSide borderSide: const BorderSide(),
     BorderRadius borderRadius: const BorderRadius.all(Radius.circular(2.0)),
     this.cut: 7.0,
     double gapPadding: 2.0,