[Gallery] Remove MaterialApp for demo screen for simplification (#197)

* Remove MaterialApp for demo screen for simplification

gallery/gallery/lib/codeviewer/code_segments.dart

@@ -198,6 +198,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'CupertinoNavigationBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        middle'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -2682,7 +2689,14 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'CupertinoNavigationBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
-      TextSpan(style: codeStyle.baseStyle, text: 'middle'),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a        middle'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'Text'),
@@ -2690,7 +2704,9 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: '_title'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: 'context'),
-      TextSpan(style: codeStyle.punctuationStyle, text: '))),'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ')),'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '),'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a      child'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -3379,6 +3395,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'CupertinoNavigationBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        middle'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a            '),
@@ -4159,6 +4182,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -5813,6 +5843,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -6326,6 +6363,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -9051,6 +9095,47 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
       TextSpan(style: codeStyle.keywordStyle, text: 'return'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.classStyle, text: 'Navigator'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      '),
+      TextSpan(
+          style: codeStyle.commentStyle,
+          text:
+              '// Adding [ValueKey] to make sure that the widget gets rebuilt when'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      '),
+      TextSpan(style: codeStyle.commentStyle, text: '// changing type.'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      key'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.classStyle, text: 'ValueKey'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(style: codeStyle.baseStyle, text: 'type'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '),'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      onGenerateRoute'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(style: codeStyle.baseStyle, text: 'settings'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ')'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '{'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a        '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'return'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(
+          style: codeStyle.classStyle, text: '_NoAnimationMaterialPageRoute'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '<'),
+      TextSpan(style: codeStyle.keywordStyle, text: 'void'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '>('),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a          builder'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(style: codeStyle.baseStyle, text: 'context'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ')'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '=>'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'Scaffold'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a            key'),
@@ -9062,6 +9147,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a              automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a              title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -9096,7 +9188,8 @@ class CodeSegments {
       TextSpan(style: codeStyle.punctuationStyle, text: ').'),
       TextSpan(style: codeStyle.baseStyle, text: 'dialogShow'),
       TextSpan(style: codeStyle.punctuationStyle, text: '),'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a          onPressed'),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                onPressed'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.punctuationStyle, text: '()'),
@@ -9123,7 +9216,8 @@ class CodeSegments {
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: 'context'),
       TextSpan(style: codeStyle.punctuationStyle, text: ');'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                      '),
       TextSpan(style: codeStyle.keywordStyle, text: 'break'),
       TextSpan(style: codeStyle.punctuationStyle, text: ';'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a                    '),
@@ -9139,7 +9233,8 @@ class CodeSegments {
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: 'context'),
       TextSpan(style: codeStyle.punctuationStyle, text: ');'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                      '),
       TextSpan(style: codeStyle.keywordStyle, text: 'break'),
       TextSpan(style: codeStyle.punctuationStyle, text: ';'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a                    '),
@@ -9155,7 +9250,8 @@ class CodeSegments {
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: 'context'),
       TextSpan(style: codeStyle.punctuationStyle, text: ');'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                      '),
       TextSpan(style: codeStyle.keywordStyle, text: 'break'),
       TextSpan(style: codeStyle.punctuationStyle, text: ';'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a                    '),
@@ -9165,7 +9261,8 @@ class CodeSegments {
       TextSpan(style: codeStyle.punctuationStyle, text: '.'),
       TextSpan(style: codeStyle.baseStyle, text: 'fullscreen'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                      '),
       TextSpan(style: codeStyle.classStyle, text: 'Navigator'),
       TextSpan(style: codeStyle.punctuationStyle, text: '.'),
       TextSpan(style: codeStyle.baseStyle, text: 'push'),
@@ -9173,9 +9270,11 @@ class CodeSegments {
       TextSpan(style: codeStyle.keywordStyle, text: 'void'),
       TextSpan(style: codeStyle.punctuationStyle, text: '>('),
       TextSpan(
-          style: codeStyle.baseStyle, text: '\u000a                  context'),
+          style: codeStyle.baseStyle,
+          text: '\u000a                        context'),
       TextSpan(style: codeStyle.punctuationStyle, text: ','),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                  '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                        '),
       TextSpan(style: codeStyle.classStyle, text: 'MaterialPageRoute'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(
@@ -9198,11 +9297,14 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.keywordStyle, text: 'true'),
       TextSpan(style: codeStyle.punctuationStyle, text: ','),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                  '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                        '),
       TextSpan(style: codeStyle.punctuationStyle, text: '),'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                      '),
       TextSpan(style: codeStyle.punctuationStyle, text: ');'),
-      TextSpan(style: codeStyle.baseStyle, text: '\u000a                '),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a                      '),
       TextSpan(style: codeStyle.keywordStyle, text: 'break'),
       TextSpan(style: codeStyle.punctuationStyle, text: ';'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a                  '),
@@ -9214,12 +9316,130 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: '\u000a            '),
       TextSpan(style: codeStyle.punctuationStyle, text: '),'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a          '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '),'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a        '),
+      TextSpan(style: codeStyle.punctuationStyle, text: ');'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '},'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
       TextSpan(style: codeStyle.punctuationStyle, text: ');'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a  '),
       TextSpan(style: codeStyle.punctuationStyle, text: '}'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a'),
       TextSpan(style: codeStyle.punctuationStyle, text: '}'),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a\u000a'),
+      TextSpan(
+          style: codeStyle.commentStyle,
+          text: '/// A MaterialPageRoute without any transition animations.'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a'),
+      TextSpan(style: codeStyle.keywordStyle, text: 'class'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(
+          style: codeStyle.classStyle, text: '_NoAnimationMaterialPageRoute'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '<'),
+      TextSpan(style: codeStyle.classStyle, text: 'T'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '>'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'extends'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.classStyle, text: 'MaterialPageRoute'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '<'),
+      TextSpan(style: codeStyle.classStyle, text: 'T'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '>'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '{'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a  '),
+      TextSpan(
+          style: codeStyle.classStyle, text: '_NoAnimationMaterialPageRoute'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '({'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
+      TextSpan(style: codeStyle.keywordStyle, text: '@required'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.classStyle, text: 'WidgetBuilder'),
+      TextSpan(style: codeStyle.baseStyle, text: ' builder'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
+      TextSpan(style: codeStyle.classStyle, text: 'RouteSettings'),
+      TextSpan(style: codeStyle.baseStyle, text: ' settings'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'bool'),
+      TextSpan(style: codeStyle.baseStyle, text: ' maintainState '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '='),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'true'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'bool'),
+      TextSpan(style: codeStyle.baseStyle, text: ' fullscreenDialog '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '='),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a  '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '})'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'super'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a            builder'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' builder'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(
+          style: codeStyle.baseStyle, text: '\u000a            maintainState'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' maintainState'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a            settings'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' settings'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a            fullscreenDialog'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' fullscreenDialog'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ');'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a\u000a  '),
+      TextSpan(style: codeStyle.keywordStyle, text: '@override'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a  '),
+      TextSpan(style: codeStyle.classStyle, text: 'Widget'),
+      TextSpan(style: codeStyle.baseStyle, text: ' buildTransitions'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(style: codeStyle.classStyle, text: 'BuildContext'),
+      TextSpan(style: codeStyle.baseStyle, text: ' context'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.classStyle, text: 'Animation'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '<'),
+      TextSpan(style: codeStyle.keywordStyle, text: 'double'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '>'),
+      TextSpan(style: codeStyle.baseStyle, text: ' animation'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a      '),
+      TextSpan(style: codeStyle.classStyle, text: 'Animation'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '<'),
+      TextSpan(style: codeStyle.keywordStyle, text: 'double'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '>'),
+      TextSpan(style: codeStyle.baseStyle, text: ' secondaryAnimation'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.classStyle, text: 'Widget'),
+      TextSpan(style: codeStyle.baseStyle, text: ' child'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ')'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '{'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a    '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'return'),
+      TextSpan(style: codeStyle.baseStyle, text: ' child'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ';'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a  '),
+      TextSpan(style: codeStyle.punctuationStyle, text: '}'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a'),
+      TextSpan(style: codeStyle.punctuationStyle, text: '}'),
+      TextSpan(style: codeStyle.baseStyle, text: '\u000a\u000a'),
       TextSpan(style: codeStyle.keywordStyle, text: 'class'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: '_DialogButton'),
@@ -13728,6 +13948,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a          automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a          title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -13883,6 +14110,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -16317,6 +16551,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a        automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),
@@ -17714,6 +17955,13 @@ class CodeSegments {
       TextSpan(style: codeStyle.baseStyle, text: ' '),
       TextSpan(style: codeStyle.classStyle, text: 'AppBar'),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
+      TextSpan(
+          style: codeStyle.baseStyle,
+          text: '\u000a          automaticallyImplyLeading'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ':'),
+      TextSpan(style: codeStyle.baseStyle, text: ' '),
+      TextSpan(style: codeStyle.keywordStyle, text: 'false'),
+      TextSpan(style: codeStyle.punctuationStyle, text: ','),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a          title'),
       TextSpan(style: codeStyle.punctuationStyle, text: ':'),
       TextSpan(style: codeStyle.baseStyle, text: ' '),

gallery/gallery/lib/data/demos.dart

@@ -31,7 +31,6 @@ import 'package:gallery/demos/material/text_field_demo.dart';
 import 'package:gallery/demos/reference/colors_demo.dart';
 import 'package:gallery/demos/reference/typography_demo.dart';
 import 'package:gallery/l10n/gallery_localizations.dart';
-import 'package:gallery/pages/demo.dart';
 import 'package:gallery/themes/material_demo_theme_data.dart';
 
 class GalleryDemo {
@@ -669,37 +668,16 @@ class DemoWrapper extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    bool hasCycled = true;
-    return MaterialApp(
-      theme: MaterialDemoThemeData.themeData.copyWith(
+    return Theme(
+      data: MaterialDemoThemeData.themeData.copyWith(
         platform: GalleryOptions.of(context).platform,
       ),
-      debugShowCheckedModeBanner: false,
-      localizationsDelegates: GalleryLocalizations.localizationsDelegates,
-      supportedLocales: GalleryLocalizations.supportedLocales,
-      locale: GalleryOptions.of(context).locale,
-      // Remove the MediaQuery padding because the demo is rendered inside of a
-      // different page that already accounts for this padding.
-      home: MediaQuery.removePadding(
-        context: context,
-        removeTop: true,
-        removeBottom: true,
-        child: Focus(
-          onFocusChange: (hasFocus) {
-            if (hasFocus && hasCycled) {
-              hasCycled = !hasCycled;
-              FocusScope.of(context).requestFocus(
-                  InheritedDemoFocusNodes.of(context).backButtonFocusNode);
-            }
-          },
       child: ApplyTextOptions(
         child: CupertinoTheme(
           data: CupertinoThemeData().copyWith(brightness: Brightness.light),
           child: child,
         ),
       ),
-        ),
-      ),
     );
   }
 }

gallery/gallery/lib/demos/cupertino/cupertino_alert_demo.dart

@@ -216,7 +216,10 @@ class _CupertinoAlertDemoState extends State<CupertinoAlertDemo> {
   @override
   Widget build(BuildContext context) {
     return CupertinoPageScaffold(
-      navigationBar: CupertinoNavigationBar(middle: Text(_title(context))),
+      navigationBar: CupertinoNavigationBar(
+        automaticallyImplyLeading: false,
+        middle: Text(_title(context)),
+      ),
       child: Builder(
         builder: (context) {
           return Column(

gallery/gallery/lib/demos/cupertino/cupertino_button_demo.dart

@@ -13,6 +13,7 @@ class CupertinoButtonDemo extends StatelessWidget {
   Widget build(BuildContext context) {
     return CupertinoPageScaffold(
       navigationBar: CupertinoNavigationBar(
+        automaticallyImplyLeading: false,
         middle:
             Text(GalleryLocalizations.of(context).demoCupertinoButtonsTitle),
       ),

gallery/gallery/lib/demos/cupertino/cupertino_segmented_control_demo.dart

@@ -37,6 +37,7 @@ class _CupertinoSegmentedControlDemoState
 
     return CupertinoPageScaffold(
       navigationBar: CupertinoNavigationBar(
+        automaticallyImplyLeading: false,
         middle: Text(
           localizations.demoCupertinoSegmentedControlTitle,
         ),

gallery/gallery/lib/demos/material/bottom_navigation_demo.dart

@@ -119,6 +119,7 @@ class _BottomNavigationDemoState extends State<BottomNavigationDemo>
 
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(_title(context)),
       ),
       body: Center(

gallery/gallery/lib/demos/material/bottom_sheet_demo.dart

@@ -50,8 +50,8 @@ class BottomSheetDemo extends StatelessWidget {
         return MaterialPageRoute<Widget>(
           builder: (context) => Scaffold(
             appBar: AppBar(
-              title: Text(_title(context)),
               automaticallyImplyLeading: false,
+              title: Text(_title(context)),
             ),
             floatingActionButton: FloatingActionButton(
               onPressed: () {},

gallery/gallery/lib/demos/material/button_demo.dart

@@ -58,6 +58,7 @@ class ButtonDemo extends StatelessWidget {
 
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(_title(context)),
       ),
       body: buttons,

gallery/gallery/lib/demos/material/chip_demo.dart

@@ -52,6 +52,7 @@ class ChipDemo extends StatelessWidget {
 
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(_title(context)),
       ),
       body: buttons,

gallery/gallery/lib/demos/material/dialog_demo.dart

@@ -124,9 +124,16 @@ class DialogDemo extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
+    return Navigator(
+      // Adding [ValueKey] to make sure that the widget gets rebuilt when
+      // changing type.
+      key: ValueKey(type),
+      onGenerateRoute: (settings) {
+        return _NoAnimationMaterialPageRoute<void>(
+          builder: (context) => Scaffold(
             key: _scaffoldKey,
             appBar: AppBar(
+              automaticallyImplyLeading: false,
               title: Text(_title(context)),
             ),
             body: Center(
@@ -156,10 +163,33 @@ class DialogDemo extends StatelessWidget {
                 },
               ),
             ),
+          ),
+        );
+      },
     );
   }
 }
 
+/// A MaterialPageRoute without any transition animations.
+class _NoAnimationMaterialPageRoute<T> extends MaterialPageRoute<T> {
+  _NoAnimationMaterialPageRoute({
+    @required WidgetBuilder builder,
+    RouteSettings settings,
+    bool maintainState = true,
+    bool fullscreenDialog = false,
+  }) : super(
+            builder: builder,
+            maintainState: maintainState,
+            settings: settings,
+            fullscreenDialog: fullscreenDialog);
+
+  @override
+  Widget buildTransitions(BuildContext context, Animation<double> animation,
+      Animation<double> secondaryAnimation, Widget child) {
+    return child;
+  }
+}
+
 class _DialogButton extends StatelessWidget {
   const _DialogButton({Key key, this.text}) : super(key: key);
 

gallery/gallery/lib/demos/material/list_demo.dart

@@ -22,6 +22,7 @@ class ListDemo extends StatelessWidget {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(GalleryLocalizations.of(context).demoListsTitle),
       ),
       body: Scrollbar(

gallery/gallery/lib/demos/material/selection_controls_demo.dart

@@ -48,6 +48,7 @@ class SelectionControlsDemo extends StatelessWidget {
 
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(_title(context)),
       ),
       body: controls,

gallery/gallery/lib/demos/material/snackbar_demo.dart

@@ -12,6 +12,7 @@ class SnackbarsDemo extends StatelessWidget {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(GalleryLocalizations.of(context).demoSnackbarsTitle),
       ),
       body: Builder(

gallery/gallery/lib/demos/material/tabs_demo.dart

@@ -23,6 +23,7 @@ class TabsDemo extends StatelessWidget {
       length: tabs.length,
       child: Scaffold(
         appBar: AppBar(
+          automaticallyImplyLeading: false,
           title: Text(GalleryLocalizations.of(context).demoTabsTitle),
           bottom: TabBar(
             isScrollable: true,

gallery/gallery/lib/demos/material/text_field_demo.dart

@@ -16,6 +16,7 @@ class TextFieldDemo extends StatelessWidget {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(GalleryLocalizations.of(context).demoTextFieldTitle),
       ),
       body: TextFormFieldDemo(),

gallery/gallery/lib/demos/reference/colors_demo.dart

@@ -243,6 +243,7 @@ class ColorsDemo extends StatelessWidget {
       length: palettes.length,
       child: Scaffold(
         appBar: AppBar(
+          automaticallyImplyLeading: false,
           title: Text(GalleryLocalizations.of(context).demoColorsTitle),
           bottom: TabBar(
             isScrollable: true,

gallery/gallery/lib/demos/reference/typography_demo.dart

@@ -117,6 +117,7 @@ class TypographyDemo extends StatelessWidget {
 
     return Scaffold(
       appBar: AppBar(
+        automaticallyImplyLeading: false,
         title: Text(GalleryLocalizations.of(context).demoTypographyTitle),
       ),
       body: Scrollbar(child: ListView(children: styleItems)),

gallery/gallery/lib/pages/demo.dart

@@ -51,7 +51,6 @@ class _DemoPageState extends State<DemoPage> with TickerProviderStateMixin {
   int _demoViewedCount;
 
   AnimationController _codeBackgroundColorController;
-  FocusNode backButonFocusNode;
 
   GalleryDemoConfiguration get _currentConfig {
     return widget.demo.configurations[_configIndex];
@@ -85,13 +84,11 @@ class _DemoPageState extends State<DemoPage> with TickerProviderStateMixin {
         preferences.setInt(_demoViewedCountKey, _demoViewedCount + 1);
       });
     });
-    backButonFocusNode = FocusNode();
   }
 
   @override
   void dispose() {
     _codeBackgroundColorController.dispose();
-    backButonFocusNode.dispose();
     super.dispose();
   }
 
@@ -191,7 +188,6 @@ class _DemoPageState extends State<DemoPage> with TickerProviderStateMixin {
         onPressed: () {
           Navigator.maybePop(context);
         },
-        focusNode: backButonFocusNode,
       ),
       actions: [
         if (_hasOptions)
@@ -487,10 +483,7 @@ class _DemoPageState extends State<DemoPage> with TickerProviderStateMixin {
       );
     }
 
-    return InheritedDemoFocusNodes(
-      backButtonFocusNode: backButonFocusNode,
-      child: FeatureDiscoveryController(page),
-    );
+    return FeatureDiscoveryController(page);
   }
 }
 
@@ -781,19 +774,3 @@ class CodeDisplayPage extends StatelessWidget {
     );
   }
 }
-
-class InheritedDemoFocusNodes extends InheritedWidget {
-  InheritedDemoFocusNodes({
-    @required Widget child,
-    @required this.backButtonFocusNode,
-  })  : assert(child != null),
-        super(child: child);
-
-  final FocusNode backButtonFocusNode;
-
-  static InheritedDemoFocusNodes of(BuildContext context) =>
-      context.dependOnInheritedWidgetOfExactType();
-
-  @override
-  bool updateShouldNotify(InheritedWidget oldWidget) => true;
-}