Fixed preferredSize getter in TabBar (#41299)

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

@@ -753,7 +753,7 @@ class TabBar extends StatefulWidget implements PreferredSizeWidget {
     for (final Widget item in tabs) {
       if (item is Tab) {
         final Tab tab = item;
-        if (tab.text != null && tab.icon != null)
+        if ((tab.text != null || tab.child != null) && tab.icon != null)
           return Size.fromHeight(_kTextAndIconTabHeight + indicatorWeight);
       }
     }

packages/flutter/test/material/tabs_test.dart

@@ -2459,4 +2459,20 @@ void main() {
     await tester.pumpAndSettle();
     expect(find.text('No tabs'), findsOneWidget);
   });
+
+   testWidgets('TabBar expands vertically to accommodate the Icon and child Text() pair the same amount it would expand for Icon and text pair.', (WidgetTester tester) async {
+    const double indicatorWeight = 2.0;
+
+    const List<Widget> tabListWithText = <Widget>[
+      Tab(icon: Icon(Icons.notifications), text: 'Test'),
+    ];
+    const List<Widget> tabListWithTextChild = <Widget>[
+      Tab(icon: Icon(Icons.notifications), child: Text('Test')),
+    ];
+
+    const TabBar tabBarWithText = TabBar(tabs: tabListWithText, indicatorWeight: indicatorWeight,);
+    const TabBar tabBarWithTextChild = TabBar(tabs: tabListWithTextChild, indicatorWeight: indicatorWeight,);
+
+    expect(tabBarWithText.preferredSize, tabBarWithTextChild.preferredSize);
+   });
 }