Fix IconButton theming in the InputDecorator (#146567)

fixes [DropdownMenu TrailingIcon can't be styled through providing an IconButtonTheme](flutter/flutter#145081) (second PR)

### Description
 This PR replaces `IconButton.style`  with `ButtonStyle` when merging parent `IconButtonTheme`  as `styleFrom` returns defaults for some properties.

Author: TahaTesser

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

@@ -9,10 +9,10 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 
+import 'button_style.dart';
 import 'color_scheme.dart';
 import 'colors.dart';
 import 'constants.dart';
-import 'icon_button.dart';
 import 'icon_button_theme.dart';
 import 'input_border.dart';
 import 'material.dart';
@@ -2245,9 +2245,11 @@ class _InputDecoratorState extends State<InputDecorator> with TickerProviderStat
               ),
               child: IconButtonTheme(
                 data: IconButtonThemeData(
-                  style: IconButton.styleFrom(
-                    foregroundColor: _getPrefixIconColor(inputDecorationTheme, iconButtonTheme, defaults),
-                    iconSize: iconSize,
+                  style: ButtonStyle(
+                    foregroundColor: WidgetStatePropertyAll<Color>(
+                      _getPrefixIconColor(inputDecorationTheme, iconButtonTheme, defaults),
+                    ),
+                    iconSize: WidgetStatePropertyAll<double>(iconSize),
                   ).merge(iconButtonTheme.style),
                 ),
                 child: Semantics(
@@ -2280,9 +2282,11 @@ class _InputDecoratorState extends State<InputDecorator> with TickerProviderStat
                 ),
                 child: IconButtonTheme(
                   data: IconButtonThemeData(
-                    style: IconButton.styleFrom(
-                      foregroundColor: _getSuffixIconColor(inputDecorationTheme, iconButtonTheme, defaults),
-                      iconSize: iconSize,
+                    style: ButtonStyle(
+                      foregroundColor: WidgetStatePropertyAll<Color>(
+                        _getSuffixIconColor(inputDecorationTheme, iconButtonTheme, defaults),
+                      ),
+                      iconSize: WidgetStatePropertyAll<double>(iconSize),
                     ).merge(iconButtonTheme.style),
                   ),
                   child: Semantics(

packages/flutter/test/material/input_decorator_test.dart

@@ -292,6 +292,10 @@ TextStyle? getIconStyle(WidgetTester tester, IconData icon) {
   return iconRichText.text.style;
 }
 
+RenderObject getOverlayColor(WidgetTester tester) {
+  return tester.allRenderObjects.firstWhere((RenderObject object) => object.runtimeType.toString() == '_RenderInkFeatures');
+}
+
 void main() {
   // TODO(bleroux): migrate all M2 tests to M3.
   // See https://github.com/flutter/flutter/issues/139076
@@ -5078,18 +5082,23 @@ void main() {
     expect(merged.constraints, overrideTheme.constraints);
   });
 
-  testWidgets('Prefix and suffix IconButtons inherit IconButtonTheme', (WidgetTester tester) async {
+  testWidgets('Prefix IconButton inherits IconButtonTheme', (WidgetTester tester) async {
     const IconData prefixIcon = Icons.person;
-    const IconData suffixIcon = Icons.search;
     const Color backgroundColor = Color(0xffff0000);
     const Color foregroundColor = Color(0xff00ff00);
-    final OutlinedBorder shape =RoundedRectangleBorder(
+    const Color overlayColor = Color(0xff0000ff);
+    const Color shadowColor = Color(0xff0ff0ff);
+    const double elevation = 4.0;
+    final RoundedRectangleBorder shape = RoundedRectangleBorder(
       borderRadius: BorderRadius.circular(10.0),
     );
-    final ButtonStyle iconButtonStyle = IconButton.styleFrom(
-      backgroundColor: backgroundColor,
-      foregroundColor: foregroundColor,
-      shape: shape,
+    final ButtonStyle iconButtonStyle = ButtonStyle(
+      backgroundColor: const MaterialStatePropertyAll<Color>(backgroundColor),
+      foregroundColor: const MaterialStatePropertyAll<Color>(foregroundColor),
+      overlayColor: const MaterialStatePropertyAll<Color>(overlayColor),
+      shadowColor: const MaterialStatePropertyAll<Color>(shadowColor),
+      elevation: const MaterialStatePropertyAll<double>(elevation),
+      shape: MaterialStatePropertyAll<OutlinedBorder>(shape),
     );
 
     await tester.pumpWidget(
@@ -5101,32 +5110,86 @@ void main() {
               onPressed: () {},
               icon: const Icon(prefixIcon),
             ),
-            suffixIcon: IconButton(
-              onPressed: () {},
-              icon: const Icon(suffixIcon),
-            ),
           ),
         ),
       ),
     );
 
-    final Finder prefixIconMaterial = find.descendant(
+    final Finder iconMaterial = find.descendant(
       of: find.widgetWithIcon(IconButton, prefixIcon),
       matching: find.byType(Material),
     );
-    Material material = tester.widget<Material>(prefixIconMaterial);
+    final Material material = tester.widget<Material>(iconMaterial);
     expect(material.color, backgroundColor);
-    expect(material.shape, iconButtonStyle.shape?.resolve(<WidgetState>{}));
-    final Finder suffixIconMaterial = find.descendant(
+    expect(material.shadowColor, shadowColor);
+    expect(material.elevation, elevation);
+    expect(material.shape, shape);
+
+    expect(getIconStyle(tester, prefixIcon)?.color, foregroundColor);
+
+    final Offset center = tester.getCenter(find.byIcon(prefixIcon));
+    final TestGesture gesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
+    await gesture.addPointer();
+    await gesture.moveTo(center);
+    await tester.pumpAndSettle();
+    expect(getOverlayColor(tester), paints..rect(color: overlayColor));
+  });
+
+  testWidgets('Suffix IconButton inherits IconButtonTheme', (WidgetTester tester) async {
+    const IconData suffixIcon = Icons.delete;
+    const Color backgroundColor = Color(0xffff0000);
+    const Color foregroundColor = Color(0xff00ff00);
+    const Color overlayColor = Color(0xff0000ff);
+    const Color shadowColor = Color(0xff0ff0ff);
+    const double elevation = 4.0;
+    final RoundedRectangleBorder shape = RoundedRectangleBorder(
+      borderRadius: BorderRadius.circular(10.0),
+    );
+    final ButtonStyle iconButtonStyle = ButtonStyle(
+      backgroundColor: const MaterialStatePropertyAll<Color>(backgroundColor),
+      foregroundColor: const MaterialStatePropertyAll<Color>(foregroundColor),
+      overlayColor: const MaterialStatePropertyAll<Color>(overlayColor),
+      shadowColor: const MaterialStatePropertyAll<Color>(shadowColor),
+      elevation: const MaterialStatePropertyAll<double>(elevation),
+      shape: MaterialStatePropertyAll<OutlinedBorder>(shape),
+    );
+
+    await tester.pumpWidget(
+      IconButtonTheme(
+        data: IconButtonThemeData(style: iconButtonStyle),
+        child: buildInputDecorator(
+          decoration: InputDecoration(
+            suffixIcon: IconButton(
+              onPressed: () {},
+              icon: const Icon(suffixIcon),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final Finder iconMaterial = find.descendant(
       of: find.widgetWithIcon(IconButton, suffixIcon),
       matching: find.byType(Material),
     );
-    material = tester.widget<Material>(suffixIconMaterial);
+    final Material material = tester.widget<Material>(iconMaterial);
     expect(material.color, backgroundColor);
+    expect(material.shadowColor, shadowColor);
+    expect(material.elevation, elevation);
     expect(material.shape, shape);
 
-    expect(getIconStyle(tester, prefixIcon)?.color, foregroundColor);
     expect(getIconStyle(tester, suffixIcon)?.color, foregroundColor);
+
+    final Offset center = tester.getCenter(find.byIcon(suffixIcon));
+    final TestGesture gesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
+    await gesture.addPointer();
+    await gesture.moveTo(center);
+    await tester.pumpAndSettle();
+    expect(getOverlayColor(tester), paints..rect(color: overlayColor));
   });
 
   testWidgets('Prefix IconButton color respects IconButtonTheme foreground color states', (WidgetTester tester) async {