Clean up golden files (#19440)

Makes them all be generated on Linux and fixes some to not be so large.

bin/internal/goldens.version

-35f172d7c241a8112db53dd9ee3c29a13cf19eb8
+4948d5d7c0e07d092bd38511e5e159007425ec48

packages/flutter/test/cupertino/segmented_control_test.dart

@@ -1165,13 +1165,6 @@ void main() {
   });
 
   testWidgets('Golden Test Placeholder Widget', (WidgetTester tester) async {
-    // Different machines render this content differently. Since the golden
-    // files are rendered on MacOS, this test should only be run on MacOS.
-    // If the golden files are regenerated on another OS, please change this
-    // test to only run on that OS.
-    if (Platform.isMacOS)
-      return;
-
     final Map<int, Widget> children = <int, Widget>{};
     children[0] = new Container();
     children[1] = const Placeholder();
@@ -1200,16 +1193,9 @@ void main() {
       find.byType(RepaintBoundary),
       matchesGoldenFile('segmented_control_test.0.0.png'),
     );
-  });
+  }, skip: !Platform.isLinux);
 
   testWidgets('Golden Test Pressed State', (WidgetTester tester) async {
-    // Different machines render this content differently. Since the golden
-    // files are rendered on MacOS, this test should only be run on MacOS.
-    // If the golden files are regenerated on another OS, please change this
-    // test to only run on that OS.
-    if (!Platform.isMacOS)
-      return;
-
     final Map<int, Widget> children = <int, Widget>{};
     children[0] = const Text('A');
     children[1] = const Text('B');
@@ -1242,5 +1228,5 @@ void main() {
       find.byType(RepaintBoundary),
       matchesGoldenFile('segmented_control_test.1.0.png'),
     );
-  });
+  }, skip: !Platform.isLinux);
 }

packages/flutter/test/widgets/text_golden_test.dart

@@ -11,8 +11,8 @@ import 'package:flutter/widgets.dart';
 void main() {
   testWidgets('Centered text', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new RepaintBoundary(
-        child: new Center(
+      new Center(
+        child: new RepaintBoundary(
           child: new Container(
             width: 200.0,
             height: 100.0,
@@ -32,12 +32,11 @@ void main() {
     await expectLater(
       find.byType(Container),
       matchesGoldenFile('text_golden.Centered.png'),
-      skip: !Platform.isLinux,
     );
 
     await tester.pumpWidget(
-      new RepaintBoundary(
-        child: new Center(
+      new Center(
+        child: new RepaintBoundary(
           child: new Container(
             width: 200.0,
             height: 100.0,
@@ -57,20 +56,22 @@ void main() {
     await expectLater(
       find.byType(Container),
       matchesGoldenFile('text_golden.Centered.wrap.png'),
-      skip: !Platform.isLinux,
     );
-  });
+  }, skip: !Platform.isLinux);
 
 
   testWidgets('Text Foreground', (WidgetTester tester) async {
     const Color black = const Color(0xFF000000);
     const Color red = const Color(0xFFFF0000);
     const Color blue = const Color(0xFF0000FF);
-    final Shader linearGradient = const LinearGradient(colors: <Color>[red, blue]).createShader(new Rect.fromLTWH(0.0, 0.0, 50.0, 20.0));
+    final Shader linearGradient = const LinearGradient(
+      colors: const <Color>[red, blue],
+    ).createShader(new Rect.fromLTWH(0.0, 0.0, 50.0, 20.0));
 
     await tester.pumpWidget(
-      new RepaintBoundary(
-        child: new Center(
+      new Align(
+        alignment: Alignment.topLeft,
+        child: new RepaintBoundary(
           child: new Text('Hello',
             textDirection: TextDirection.ltr,
             style: new TextStyle(
@@ -86,16 +87,14 @@ void main() {
     await expectLater(
       find.byType(RepaintBoundary),
       matchesGoldenFile('text_golden.Foreground.gradient.png'),
-      // this was generated on MacOS and will fail on Linux
-      // change to !Platform.isLinux once they're properly generated
-      skip: true, // !Platform.isLinux,
     );
 
     await tester.pumpWidget(
-      new RepaintBoundary(
-        child: new Center(
-          child: new Text('Hello', 
-            textDirection: TextDirection.ltr,          
+      new Align(
+        alignment: Alignment.topLeft,
+        child: new RepaintBoundary(
+          child: new Text('Hello',
+            textDirection: TextDirection.ltr,
             style: new TextStyle(
               foreground: new Paint()
                 ..color = black
@@ -110,16 +109,14 @@ void main() {
     await expectLater(
       find.byType(RepaintBoundary),
       matchesGoldenFile('text_golden.Foreground.stroke.png'),
-      // this was generated on MacOS and will fail on Linux
-      // change to !Platform.isLinux once they're properly generated
-      skip: true, // !Platform.isLinux,
     );
 
     await tester.pumpWidget(
-      new RepaintBoundary(
-        child: new Center(
-          child: new Text('Hello', 
-            textDirection: TextDirection.ltr,          
+      new Align(
+        alignment: Alignment.topLeft,
+        child: new RepaintBoundary(
+          child: new Text('Hello',
+            textDirection: TextDirection.ltr,
             style: new TextStyle(
               foreground: new Paint()
                 ..color = black
@@ -135,11 +132,8 @@ void main() {
     await expectLater(
       find.byType(RepaintBoundary),
       matchesGoldenFile('text_golden.Foreground.stroke_and_gradient.png'),
-      // this was generated on MacOS and will fail on Linux
-      // change to !Platform.isLinux once they're properly generated
-      skip: true, // !Platform.isLinux,
     );
-  });
+  }, skip: !Platform.isLinux);
 
   testWidgets('Text Fade', (WidgetTester tester) async {
     await tester.pumpWidget(
@@ -174,7 +168,6 @@ void main() {
     await expectLater(
       find.byType(RepaintBoundary).first,
       matchesGoldenFile('text_golden.Fade.1.png'),
-      skip: !Platform.isLinux,
     );
-  });
+  }, skip: !Platform.isLinux);
 }