Move FlutterLogo from material to widget (#155864)

The PR is moving FlutterLogo from `lib/src/material` to `lib/src/widgets` because it has no dependency on Material.

Issue: flutter/flutter#154448

PS: There is [older PR](flutter/flutter#154711) for this issue and I don't know the policy on conflicting PRs. Let me know if I need to drop mine.

Author: g0rdan

dev/integration_tests/flutter_gallery/lib/demo/cupertino/cupertino_segmented_control_demo.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
-import 'package:flutter/material.dart';
 
 import '../../gallery/demo.dart';
 

examples/api/lib/cupertino/context_menu/cupertino_context_menu.0.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
-import 'package:flutter/material.dart';
 
 /// Flutter code sample for [CupertinoContextMenu].
 

examples/api/lib/cupertino/context_menu/cupertino_context_menu.1.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
-import 'package:flutter/material.dart';
 
 /// Flutter code sample for [CupertinoContextMenu].
 

packages/flutter/lib/material.dart

@@ -92,7 +92,6 @@ export 'src/material/flexible_space_bar.dart';
 export 'src/material/floating_action_button.dart';
 export 'src/material/floating_action_button_location.dart';
 export 'src/material/floating_action_button_theme.dart';
-export 'src/material/flutter_logo.dart';
 export 'src/material/grid_tile.dart';
 export 'src/material/grid_tile_bar.dart';
 export 'src/material/icon_button.dart';

packages/flutter/lib/src/material/flutter_logo.dart renamed to packages/flutter/lib/src/widgets/flutter_logo.dart

@@ -2,7 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter/widgets.dart';
+import 'basic.dart';
+import 'framework.dart';
+import 'icon_theme.dart';
+import 'icon_theme_data.dart';
+import 'implicit_animations.dart';
 
 /// The Flutter logo, in widget form. This widget respects the [IconTheme].
 /// For guidelines on using the Flutter logo, visit https://flutter.dev/brand.

packages/flutter/lib/widgets.dart

@@ -52,6 +52,7 @@ export 'src/widgets/dual_transition_builder.dart';
 export 'src/widgets/editable_text.dart';
 export 'src/widgets/fade_in_image.dart';
 export 'src/widgets/feedback.dart';
+export 'src/widgets/flutter_logo.dart';
 export 'src/widgets/focus_manager.dart';
 export 'src/widgets/focus_scope.dart';
 export 'src/widgets/focus_traversal.dart';

packages/flutter/test/material/flutter_logo_test.dart renamed to packages/flutter/test/widgets/flutter_logo_test.dart

@@ -7,7 +7,7 @@
 @Tags(<String>['reduced-test-set'])
 library;
 
-import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {