Show search app bar theme (#37962)

Use the entire appBarTheme from the showSearch delegate for the search pages appBar theme, rather than just a select set of fields.

packages/flutter/lib/src/material/search.dart

@@ -198,6 +198,9 @@ abstract class SearchDelegate<T> {
       primaryIconTheme: theme.primaryIconTheme.copyWith(color: Colors.grey),
       primaryColorBrightness: Brightness.light,
       primaryTextTheme: theme.textTheme,
+      inputDecorationTheme: theme.inputDecorationTheme.copyWith(
+        border: InputBorder.none,
+      ),
     );
   }
 
@@ -500,28 +503,24 @@ class _SearchPageState<T> extends State<_SearchPage<T>> {
       namesRoute: true,
       label: routeName,
       child: Scaffold(
-        appBar: AppBar(
-          backgroundColor: theme.primaryColor,
-          iconTheme: theme.primaryIconTheme,
-          textTheme: theme.primaryTextTheme,
-          brightness: theme.primaryColorBrightness,
-          leading: widget.delegate.buildLeading(context),
-          title: TextField(
-            controller: widget.delegate._queryTextController,
-            focusNode: focusNode,
-            style: theme.textTheme.title,
-            textInputAction: widget.delegate.textInputAction,
-            keyboardType: widget.delegate.keyboardType,
-            onSubmitted: (String _) {
-              widget.delegate.showResults(context);
-            },
-            decoration: InputDecoration(
-              border: InputBorder.none,
-              hintText: searchFieldLabel,
-              hintStyle: theme.inputDecorationTheme.hintStyle,
+        appBar: _ThemedPreferredSizeWidget(
+          theme: theme,
+          child: AppBar(
+            leading: widget.delegate.buildLeading(context),
+            title: TextField(
+              controller: widget.delegate._queryTextController,
+              focusNode: focusNode,
+              textInputAction: widget.delegate.textInputAction,
+              keyboardType: widget.delegate.keyboardType,
+              onSubmitted: (String _) {
+                widget.delegate.showResults(context);
+              },
+              decoration: InputDecoration(
+                hintText: searchFieldLabel,
+              ),
             ),
+            actions: widget.delegate.buildActions(context),
           ),
-          actions: widget.delegate.buildActions(context),
         ),
         body: AnimatedSwitcher(
           duration: const Duration(milliseconds: 300),
@@ -531,3 +530,21 @@ class _SearchPageState<T> extends State<_SearchPage<T>> {
     );
   }
 }
+
+class _ThemedPreferredSizeWidget extends StatelessWidget implements PreferredSizeWidget {
+  const _ThemedPreferredSizeWidget({ this.theme, this.child });
+
+  final ThemeData theme;
+  final PreferredSizeWidget child;
+
+  @override
+  Widget build(BuildContext context) {
+    return Theme(
+      data: theme,
+      child: child,
+    );
+  }
+
+  @override
+  Size get preferredSize => child.preferredSize;
+}

packages/flutter/test/material/search_test.dart

@@ -100,9 +100,13 @@ void main() {
     await tester.tap(find.byTooltip('Search'));
     await tester.pumpAndSettle();
 
-    final TextField textField = tester.widget<TextField>(find.byType(TextField));
-    final Color hintColor = textField.decoration.hintStyle.color;
-    expect(hintColor, delegate.hintTextColor);
+    expect(tester.widget<RichText>(
+      find.descendant(
+        of: find.byType(TextField),
+        matching: find.byType(RichText),
+      )).text.style.color,
+      Colors.green,
+    );
   });
 
   testWidgets('Requests suggestions', (WidgetTester tester) async {
@@ -638,6 +642,49 @@ void main() {
       semantics.dispose();
     });
   });
+
+  testWidgets('delegate appBarTheme is applied to the AppBar color on the search page', (WidgetTester tester) async {
+    final _AppBarThemeTestDelegate delegate = _AppBarThemeTestDelegate(
+      appBarColor: Colors.green,
+    );
+    await tester.pumpWidget(TestHomePage(
+      delegate: delegate,
+    ));
+
+    // Open the search page.
+    await tester.tap(find.byTooltip('Search'));
+    await tester.pumpAndSettle();
+
+    expect(tester.widget<Material>(
+      find.descendant(
+        of: find.byType(AppBar),
+        matching: find.byType(Material),
+      )).color,
+      Colors.green,
+    );
+  });
+
+  testWidgets('delegate appBarTheme is applied to the enabledBorder of the TextField on the search page', (WidgetTester tester) async {
+    final _AppBarThemeTestDelegate delegate = _AppBarThemeTestDelegate(
+      enabledBorder: InputBorder.none,
+    );
+    await tester.pumpWidget(TestHomePage(
+      delegate: delegate,
+    ));
+
+    // Open the search page.
+    await tester.tap(find.byTooltip('Search'));
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byType(TextField), 'abc');
+
+    expect(tester.widget<InputDecorator>(
+      find.descendant(
+        of: find.byType(AppBar),
+        matching: find.byType(InputDecorator),
+      )).decoration.enabledBorder,
+      InputBorder.none,
+    );
+  });
 }
 
 class TestHomePage extends StatelessWidget {
@@ -748,3 +795,24 @@ class _TestSearchDelegate extends SearchDelegate<String> {
     return actions;
   }
 }
+
+class _AppBarThemeTestDelegate extends _TestSearchDelegate {
+  _AppBarThemeTestDelegate({this.appBarColor, this.enabledBorder});
+
+  final Color appBarColor;
+  final InputBorder enabledBorder;
+
+  @override
+  ThemeData appBarTheme(BuildContext context) {
+    final ThemeData theme = Theme.of(context);
+    return theme.copyWith(
+      primaryColor: appBarColor,
+      appBarTheme: theme.appBarTheme.copyWith(
+        color: appBarColor,
+      ),
+      inputDecorationTheme: theme.inputDecorationTheme.copyWith(
+        enabledBorder: enabledBorder,
+      ),
+    );
+  }
+}