Fix RTL icons (#15095)

examples/flutter_gallery/lib/demo/material/icons_demo.dart

@@ -52,28 +52,28 @@ class IconsDemoState extends State<IconsDemo> {
       ),
       body: new IconTheme(
         data: new IconThemeData(color: iconColor),
-        child: new Padding(
-          padding: const EdgeInsets.all(24.0),
         child: new SafeArea(
           top: false,
           bottom: false,
-            child: new Column(
+          child: new ListView(
+            padding: const EdgeInsets.all(24.0),
             children: <Widget>[
-                new _IconsDemoCard(handleIconButtonPress),
+              new _IconsDemoCard(handleIconButtonPress, Icons.face), // direction-agnostic icon
+              const SizedBox(height: 24.0),
+              new _IconsDemoCard(handleIconButtonPress, Icons.battery_unknown), // direction-aware icon
             ],
           ),
         ),
       ),
-      ),
     );
   }
 }
 
 class _IconsDemoCard extends StatelessWidget {
-
-  const _IconsDemoCard(this.handleIconButtonPress);
+  const _IconsDemoCard(this.handleIconButtonPress, this.icon);
 
   final VoidCallback handleIconButtonPress;
+  final IconData icon;
 
   Widget _buildIconButton(double iconSize, IconData icon, bool enabled) {
     return new IconButton(
@@ -95,8 +95,8 @@ class _IconsDemoCard extends StatelessWidget {
     return new TableRow(
       children: <Widget> [
         _centeredText(size.floor().toString()),
-        _buildIconButton(size, Icons.face, true),
-        _buildIconButton(size, Icons.face, false),
+        _buildIconButton(size, icon, true),
+        _buildIconButton(size, icon, false),
       ],
     );
   }

packages/flutter/lib/src/widgets/icon.dart

@@ -151,7 +151,7 @@ class Icon extends StatelessWidget {
       switch (textDirection) {
         case TextDirection.rtl:
           iconWidget = new Transform(
-            transform: new Matrix4.identity()..scale(-1.0),
+            transform: new Matrix4.identity()..scale(-1.0, 1.0, 1.0),
             alignment: Alignment.center,
             transformHitTests: false,
             child: iconWidget,