Add `PopupMenuButton.iconColor`, `PopupMenuTheme.iconSize` and fix button icon...

Add `PopupMenuButton.iconColor`, `PopupMenuTheme.iconSize` and fix button icon using unexpected color propert (#132054)

fixes [PopupMenuButton uses color property for icon color](https://github.com/flutter/flutter/issues/127802) 
fixes [`popup_menu_test.dart` lacks default icon color tests.](https://github.com/flutter/flutter/issues/132050) 

### Description
- Add  `PopupMenuButton..iconColor` and fix the PopupMenu button icon using an unexpected color property.
- Add the missing `PopupMenuTheme.iconSize`.
- Clean up some tests and minor improvements.

### Code sample

<details> 
<summary>expand to view the code sample</summary> 

```dart
import 'package:flutter/material.dart';

/// Flutter code sample for [PopupMenuButton].

// This is the type used by the popup menu below.
enum SampleItem { itemOne, itemTwo, itemThree }

void main() => runApp(const PopupMenuApp());

class PopupMenuApp extends StatelessWidget {
  const PopupMenuApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        popupMenuTheme: PopupMenuThemeData(
          // iconSize: 75,
          // iconColor: Colors.amber,
          color: Colors.deepPurple[100],
        ),
      ),
      home: const PopupMenuExample(),
    );
  }
}

class PopupMenuExample extends StatefulWidget {
  const PopupMenuExample({super.key});

  @override
  State<PopupMenuExample> createState() => _PopupMenuExampleState();
}

class _PopupMenuExampleState extends State<PopupMenuExample> {
  SampleItem? selectedMenu;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('PopupMenuButton')),
      body: Center(
        child: PopupMenuButton<SampleItem>(
          iconSize: 75,
          // iconColor: Colors.amber,
          color: Colors.deepPurple[100],
          initialValue: selectedMenu,
          // Callback that sets the selected popup menu item.
          onSelected: (SampleItem item) {
            setState(() {
              selectedMenu = item;
            });
          },
          itemBuilder: (BuildContext context) => <PopupMenuEntry<SampleItem>>[
            const PopupMenuItem<SampleItem>(
              value: SampleItem.itemOne,
              child: Text('Item 1'),
            ),
            const PopupMenuItem<SampleItem>(
              value: SampleItem.itemTwo,
              child: Text('Item 2'),
            ),
            const PopupMenuDivider(),
            const CheckedPopupMenuItem<SampleItem>(
              value: SampleItem.itemThree,
              checked: true,
              child: Text('Item 3'),
            ),
          ],
        ),
      ),
    );
  }
}

``` 
	
</details>

![Group 2](https://github.com/flutter/flutter/assets/48603081/eb5404ae-2a07-4374-9821-66a0bbea041e)

![Group 1](https://github.com/flutter/flutter/assets/48603081/464e3957-1afb-4118-abcc-aad12591dc51)

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

@@ -1111,6 +1111,7 @@ class PopupMenuButton<T> extends StatefulWidget {
     this.enabled = true,
     this.shape,
     this.color,
+    this.iconColor,
     this.enableFeedback,
     this.constraints,
     this.position,
@@ -1221,6 +1222,13 @@ class PopupMenuButton<T> extends StatefulWidget {
   /// Theme.of(context).cardColor is used.
   final Color? color;
 
+  /// If provided, this color is used for the button icon.
+  ///
+  /// If this property is null, then [PopupMenuThemeData.iconColor] is used.
+  /// If [PopupMenuThemeData.iconColor] is also null then defaults to
+  /// [IconThemeData.color].
+  final Color? iconColor;
+
   /// Whether detected gestures should provide acoustic and/or haptic feedback.
   ///
   /// For example, on Android a tap will produce a clicking sound and a
@@ -1355,6 +1363,7 @@ class PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
   @override
   Widget build(BuildContext context) {
     final IconThemeData iconTheme = IconTheme.of(context);
+    final PopupMenuThemeData popupMenuTheme = PopupMenuTheme.of(context);
     final bool enableFeedback = widget.enableFeedback
       ?? PopupMenuTheme.of(context).enableFeedback
       ?? true;
@@ -1378,8 +1387,8 @@ class PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
       icon: widget.icon ?? Icon(Icons.adaptive.more),
       padding: widget.padding,
       splashRadius: widget.splashRadius,
-      iconSize: widget.iconSize ?? iconTheme.size,
-      color: widget.color ?? iconTheme.color,
+      iconSize: widget.iconSize ?? popupMenuTheme.iconSize ?? iconTheme.size,
+      color: widget.iconColor ?? popupMenuTheme.iconColor ?? iconTheme.color,
       tooltip: widget.tooltip ?? MaterialLocalizations.of(context).showMenuTooltip,
       onPressed: widget.enabled ? showButtonMenu : null,
       enableFeedback: enableFeedback,

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

@@ -55,6 +55,8 @@ class PopupMenuThemeData with Diagnosticable {
     this.enableFeedback,
     this.mouseCursor,
     this.position,
+    this.iconColor,
+    this.iconSize,
   });
 
   /// The background color of the popup menu.
@@ -95,6 +97,12 @@ class PopupMenuThemeData with Diagnosticable {
   /// popup menu appear directly over the button that was used to create it.
   final PopupMenuPosition? position;
 
+  /// The color of the icon in the popup menu button.
+  final Color? iconColor;
+
+  /// The size of the icon in the popup menu button.
+  final double? iconSize;
+
   /// Creates a copy of this object with the given fields replaced with the
   /// new values.
   PopupMenuThemeData copyWith({
@@ -108,6 +116,8 @@ class PopupMenuThemeData with Diagnosticable {
     bool? enableFeedback,
     MaterialStateProperty<MouseCursor?>? mouseCursor,
     PopupMenuPosition? position,
+    Color? iconColor,
+    double? iconSize,
   }) {
     return PopupMenuThemeData(
       color: color ?? this.color,
@@ -120,6 +130,8 @@ class PopupMenuThemeData with Diagnosticable {
       enableFeedback: enableFeedback ?? this.enableFeedback,
       mouseCursor: mouseCursor ?? this.mouseCursor,
       position: position ?? this.position,
+      iconColor: iconColor ?? this.iconColor,
+      iconSize: iconSize ?? this.iconSize,
     );
   }
 
@@ -143,6 +155,8 @@ class PopupMenuThemeData with Diagnosticable {
       enableFeedback: t < 0.5 ? a?.enableFeedback : b?.enableFeedback,
       mouseCursor: t < 0.5 ? a?.mouseCursor : b?.mouseCursor,
       position: t < 0.5 ? a?.position : b?.position,
+      iconColor: Color.lerp(a?.iconColor, b?.iconColor, t),
+      iconSize: lerpDouble(a?.iconSize, b?.iconSize, t),
     );
   }
 
@@ -158,6 +172,8 @@ class PopupMenuThemeData with Diagnosticable {
     enableFeedback,
     mouseCursor,
     position,
+    iconColor,
+    iconSize,
   );
 
   @override
@@ -178,7 +194,9 @@ class PopupMenuThemeData with Diagnosticable {
         && other.labelTextStyle == labelTextStyle
         && other.enableFeedback == enableFeedback
         && other.mouseCursor == mouseCursor
-        && other.position == position;
+        && other.position == position
+        && other.iconColor == iconColor
+        && other.iconSize == iconSize;
   }
 
   @override
@@ -194,6 +212,8 @@ class PopupMenuThemeData with Diagnosticable {
     properties.add(DiagnosticsProperty<bool>('enableFeedback', enableFeedback, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<MouseCursor?>>('mouseCursor', mouseCursor, defaultValue: null));
     properties.add(EnumProperty<PopupMenuPosition?>('position', position, defaultValue: null));
+    properties.add(ColorProperty('iconColor', iconColor, defaultValue: null));
+    properties.add(DoubleProperty('iconSize', iconSize, defaultValue: null));
   }
 }
 

packages/flutter/test/material/popup_menu_test.dart

@@ -199,7 +199,7 @@ void main() {
     expect(cancels, equals(2));
   });
 
-  testWidgets('disabled PopupMenuButton will not call itemBuilder, onOpened, onSelected or onCanceled', (WidgetTester tester) async {
+  testWidgets('Disabled PopupMenuButton will not call itemBuilder, onOpened, onSelected or onCanceled', (WidgetTester tester) async {
     final GlobalKey popupButtonKey = GlobalKey();
     bool itemBuilderCalled = false;
     bool onOpenedCalled = false;
@@ -326,7 +326,7 @@ void main() {
     expect(onSelectedCalled, isFalse);
   });
 
-  testWidgets('disabled PopupMenuButton is focusable with directional navigation', (WidgetTester tester) async {
+  testWidgets('Disabled PopupMenuButton is focusable with directional navigation', (WidgetTester tester) async {
     final Key popupButtonKey = UniqueKey();
     final GlobalKey childKey = GlobalKey();
 
@@ -1084,7 +1084,7 @@ void main() {
     expect(tester.getTopLeft(find.byWidgetPredicate((Widget w) => '${w.runtimeType}' == '_PopupMenu<int?>')), const Offset(50.0, 50.0));
   });
 
-  testWidgets('open PopupMenu has correct semantics', (WidgetTester tester) async {
+  testWidgets('Opened PopupMenu has correct semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
     await tester.pumpWidget(
       MaterialApp(
@@ -1296,7 +1296,7 @@ void main() {
     semantics.dispose();
   });
 
-  testWidgets('disabled PopupMenuItem has correct semantics', (WidgetTester tester) async {
+  testWidgets('Disabled PopupMenuItem has correct semantics', (WidgetTester tester) async {
     // Regression test for https://github.com/flutter/flutter/issues/45044.
     final SemanticsTester semantics = SemanticsTester(tester);
     await tester.pumpWidget(
@@ -2576,32 +2576,30 @@ void main() {
     });
   });
 
-  testWidgets('iconSize parameter tests', (WidgetTester tester) async {
-    Future<void> buildFrame({double? iconSize}) {
-      return tester.pumpWidget(
-        MaterialApp(
-          home: Scaffold(
-            body: Center(
-              child: PopupMenuButton<String>(
-                iconSize: iconSize,
-                itemBuilder: (_) => <PopupMenuEntry<String>>[
-                  const PopupMenuItem<String>(
-                    value: 'value',
-                    child: Text('child'),
-                  ),
-                ],
-              ),
+  testWidgets('Can customize PopupMenuButton icon', (WidgetTester tester) async {
+    const Color iconColor = Color(0xffffff00);
+    const double iconSize = 29.5;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: PopupMenuButton<String>(
+              iconColor: iconColor,
+              iconSize: iconSize,
+              itemBuilder: (_) => <PopupMenuEntry<String>>[
+                const PopupMenuItem<String>(
+                  value: 'value',
+                  child: Text('child'),
+                ),
+              ],
             ),
           ),
         ),
-      );
-    }
-
-    await buildFrame();
-    expect(tester.getSize(find.byIcon(Icons.adaptive.more)), const Size(24, 24));
+      ),
+    );
 
-    await buildFrame(iconSize: 50);
-    expect(tester.getSize(find.byIcon(Icons.adaptive.more)), const Size(50, 50));
+    expect(_iconStyle(tester, Icons.adaptive.more)?.color, iconColor);
+    expect(tester.getSize(find.byIcon(Icons.adaptive.more)), const Size(iconSize, iconSize));
   });
 
   testWidgets('does not crash in small overlay', (WidgetTester tester) async {
@@ -3265,7 +3263,7 @@ void main() {
     expect(childBottomLeft, menuTopLeft);
   });
 
-  testWidgets('PopupmenuItem onTap should be calling after Navigator.pop', (WidgetTester tester) async {
+  testWidgets('PopupMenuItem onTap should be calling after Navigator.pop', (WidgetTester tester) async {
     await tester.pumpWidget(
       MaterialApp(
         home: Scaffold(
@@ -3494,3 +3492,10 @@ TextStyle? _labelStyle(WidgetTester tester, String label) {
     matching: find.byType(RichText),
   )).text.style;
 }
+
+TextStyle? _iconStyle(WidgetTester tester, IconData icon) {
+  return tester.widget<RichText>(find.descendant(
+    of: find.byIcon(icon),
+    matching: find.byType(RichText),
+  )).text.style;
+}

packages/flutter/test/material/popup_menu_theme_test.dart

@@ -43,6 +43,8 @@ PopupMenuThemeData _popupMenuThemeM3() {
       }
       return SystemMouseCursors.alias;
     }),
+    iconColor: const Color(0xfff12099),
+    iconSize: 17.0,
   );
 }
 
@@ -86,19 +88,23 @@ void main() {
   testWidgetsWithLeakTracking('PopupMenuThemeData implements debugFillProperties', (WidgetTester tester) async {
     final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
      PopupMenuThemeData(
-      color: const Color(0xFFFFFFFF),
+      color: const Color(0xfffffff1),
       shape: const RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(2.0))),
       elevation: 2.0,
-      shadowColor: const Color(0xff00ff00),
-      surfaceTintColor: const Color(0xff00ff00),
-      textStyle: const TextStyle(color: Color(0xffffffff)),
+      shadowColor: const Color(0xfffffff2),
+      surfaceTintColor: const Color(0xfffffff3),
+      textStyle: const TextStyle(color: Color(0xfffffff4)),
       labelTextStyle: MaterialStateProperty.resolveWith((Set<MaterialState> states) {
         if (states.contains(MaterialState.disabled)) {
-          return const TextStyle(color: Color(0xfff99ff0), fontSize: 12.0);
+          return const TextStyle(color: Color(0xfffffff5), fontSize: 12.0);
         }
-        return const TextStyle(color: Color(0xfff12099), fontSize: 17.0);
+        return const TextStyle(color: Color(0xfffffff6), fontSize: 17.0);
       }),
+      enableFeedback: false,
       mouseCursor: MaterialStateMouseCursor.clickable,
+      position: PopupMenuPosition.over,
+      iconColor: const Color(0xfffffff8),
+      iconSize: 31.0,
     ).debugFillProperties(builder);
 
     final List<String> description = builder.properties
@@ -107,14 +113,18 @@ void main() {
         .toList();
 
     expect(description, <String>[
-      'color: Color(0xffffffff)',
+      'color: Color(0xfffffff1)',
       'shape: RoundedRectangleBorder(BorderSide(width: 0.0, style: none), BorderRadius.circular(2.0))',
       'elevation: 2.0',
-      'shadowColor: Color(0xff00ff00)',
-      'surfaceTintColor: Color(0xff00ff00)',
-      'text style: TextStyle(inherit: true, color: Color(0xffffffff))',
+      'shadowColor: Color(0xfffffff2)',
+      'surfaceTintColor: Color(0xfffffff3)',
+      'text style: TextStyle(inherit: true, color: Color(0xfffffff4))',
       "labelTextStyle: Instance of '_MaterialStatePropertyWith<TextStyle?>'",
+      'enableFeedback: false',
       'mouseCursor: MaterialStateMouseCursor(clickable)',
+      'position: over',
+      'iconColor: Color(0xfffffff8)',
+      'iconSize: 31.0'
     ]);
   });
 
@@ -165,6 +175,9 @@ void main() {
       ),
     ));
 
+    // Test default button icon color.
+    expect(_iconStyle(tester, Icons.adaptive.more)?.color, theme.iconTheme.color);
+
     await tester.tap(find.byKey(popupButtonKey));
     await tester.pumpAndSettle();
 
@@ -282,6 +295,9 @@ void main() {
       ),
     ));
 
+    expect(_iconStyle(tester, Icons.adaptive.more)?.color, popupMenuTheme.iconColor);
+    expect(tester.getSize(find.byIcon(Icons.adaptive.more)), Size(popupMenuTheme.iconSize!, popupMenuTheme.iconSize!));
+
     await tester.tap(find.byKey(popupButtonKey));
     await tester.pumpAndSettle();
 
@@ -354,15 +370,17 @@ void main() {
     final Key popupButtonApp = UniqueKey();
     final Key popupItemKey = UniqueKey();
 
-    const Color color = Colors.purple;
-    const Color surfaceTintColor = Colors.amber;
-    const Color shadowColor = Colors.green;
+    const Color color = Color(0xfff11fff);
+    const Color surfaceTintColor = Color(0xfff12fff);
+    const Color shadowColor = Color(0xfff13fff);
     const ShapeBorder shape = RoundedRectangleBorder(
       borderRadius: BorderRadius.all(Radius.circular(9.0)),
     );
     const double elevation = 7.0;
-    const TextStyle textStyle = TextStyle(color: Color(0xffffffef), fontSize: 19.0);
+    const TextStyle textStyle = TextStyle(color: Color(0xfff14fff), fontSize: 19.0);
     const MouseCursor cursor =  SystemMouseCursors.forbidden;
+    const Color iconColor = Color(0xfff15fff);
+    const double iconSize = 21.5;
 
     await tester.pumpWidget(MaterialApp(
       theme: ThemeData(useMaterial3: true, popupMenuTheme: popupMenuTheme),
@@ -377,6 +395,8 @@ void main() {
               surfaceTintColor: surfaceTintColor,
               color: color,
               shape: shape,
+              iconColor: iconColor,
+              iconSize: iconSize,
               itemBuilder: (BuildContext context) {
                 return <PopupMenuEntry<void>>[
                   PopupMenuItem<void>(
@@ -398,6 +418,9 @@ void main() {
       ),
     ));
 
+    expect(_iconStyle(tester, Icons.adaptive.more)?.color, iconColor);
+    expect(tester.getSize(find.byIcon(Icons.adaptive.more)), const Size(iconSize, iconSize));
+
     await tester.tap(find.byKey(popupButtonKey));
     await tester.pumpAndSettle();
 
@@ -719,3 +742,10 @@ void main() {
 
 Set<MaterialState> enabled = <MaterialState>{};
 Set<MaterialState> disabled = <MaterialState>{MaterialState.disabled};
+
+TextStyle? _iconStyle(WidgetTester tester, IconData icon) {
+  return tester.widget<RichText>(find.descendant(
+    of: find.byIcon(icon),
+    matching: find.byType(RichText),
+  )).text.style;
+}