Apply media padding in ListTile (#13545)

Applies media padding (e.g. iOS safe area insets) around the list tile
children inside the InkWell.

Also adds safe area around gallery section titles for consistency with
surrounding list tiles.

examples/flutter_gallery/lib/gallery/home.dart

@@ -144,7 +144,11 @@ class GalleryHomeState extends State<GalleryHome> with SingleTickerProviderState
               height: 48.0,
               padding: const EdgeInsetsDirectional.only(start: 16.0),
               alignment: AlignmentDirectional.centerStart,
-              child: new Text(galleryItem.category, style: headerStyle)
+              child: new SafeArea(
+                top: false,
+                bottom: false,
+                child: new Text(galleryItem.category, style: headerStyle),
+              ),
             ),
           )
         );

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

@@ -457,8 +457,12 @@ class ListTile extends StatelessWidget {
           padding: const EdgeInsets.symmetric(horizontal: 16.0),
           child: new UnconstrainedBox(
             constrainedAxis: Axis.horizontal,
+            child: new SafeArea(
+              top: false,
+              bottom: false,
               child: new Row(children: children),
             ),
+          ),
         )
       ),
     );

packages/flutter/test/material/control_list_tile_test.dart

@@ -11,9 +11,12 @@ import 'package:flutter/rendering.dart';
 import '../widgets/semantics_tester.dart';
 
 Widget wrap({ Widget child }) {
-  return new Directionality(
+  return new MediaQuery(
+    data: const MediaQueryData(),
+    child: new Directionality(
       textDirection: TextDirection.ltr,
       child: new Material(child: child),
+    ),
   );
 }
 

packages/flutter/test/material/list_tile_test.dart

@@ -49,11 +49,16 @@ void main() {
     final Key trailingKey = new GlobalKey();
     bool hasSubtitle;
 
+    const double leftPadding = 10.0;
+    const double rightPadding = 20.0;
     Widget buildFrame({ bool dense: false, bool isTwoLine: false, bool isThreeLine: false, double textScaleFactor: 1.0 }) {
       hasSubtitle = isTwoLine || isThreeLine;
       return new MaterialApp(
         home: new MediaQuery(
-          data: new MediaQueryData(textScaleFactor: textScaleFactor),
+          data: new MediaQueryData(
+            padding: const EdgeInsets.only(left: leftPadding, right: rightPadding),
+            textScaleFactor: textScaleFactor,
+          ),
           child: new Material(
             child: new Center(
               child: new ListTile(
@@ -89,13 +94,14 @@ void main() {
 
 
     // 16.0 padding to the left and right of the leading and trailing widgets
+    // plus the media padding.
     void testHorizontalGeometry() {
-      expect(leftKey(leadingKey), 16.0);
-      expect(left('title'), 72.0);
+      expect(leftKey(leadingKey), 16.0 + leftPadding);
+      expect(left('title'), 72.0 + leftPadding);
       if (hasSubtitle)
-        expect(left('subtitle'), 72.0);
+        expect(left('subtitle'), 72.0 + leftPadding);
       expect(left('title'), rightKey(leadingKey) + 32.0);
-      expect(rightKey(trailingKey), 800.0 - 16.0);
+      expect(rightKey(trailingKey), 800.0 - 16.0 - rightPadding);
       expect(widthKey(trailingKey), 24.0);
     }
 
@@ -169,7 +175,13 @@ void main() {
 
 
   testWidgets('ListTile geometry (RTL)', (WidgetTester tester) async {
-    await tester.pumpWidget(const Directionality(
+    const double leftPadding = 10.0;
+    const double rightPadding = 20.0;
+    await tester.pumpWidget(const MediaQuery(
+      data: const MediaQueryData(
+        padding: const EdgeInsets.only(left: leftPadding, right: rightPadding),
+      ),
+      child: const Directionality(
         textDirection: TextDirection.rtl,
         child: const Material(
           child: const Center(
@@ -180,16 +192,17 @@ void main() {
             ),
           ),
         ),
+      ),
     ));
 
     double left(String text) => tester.getTopLeft(find.text(text)).dx;
     double right(String text) => tester.getTopRight(find.text(text)).dx;
 
     void testHorizontalGeometry() {
-      expect(right('leading'), 800.0 - 16.0);
-      expect(right('title'), 800.0 - 72.0);
+      expect(right('leading'), 800.0 - 16.0 - rightPadding);
+      expect(right('title'), 800.0 - 72.0 - rightPadding);
       expect(left('leading') - right('title'), 16.0);
-      expect(left('trailing'), 16.0);
+      expect(left('trailing'), 16.0 + leftPadding);
     }
 
     testHorizontalGeometry();