Constants! Constants everywhere! (#9286) Aggressively apply the const lint.

diff --git a/examples/layers/widgets/custom_render_box.dart b/examples/layers/widgets/custom_render_box.dart
index b93d8bc..f5fa0f5 100644
--- a/examples/layers/widgets/custom_render_box.dart
+++ b/examples/layers/widgets/custom_render_box.dart

@@ -46,5 +46,5 @@
 }
 
 void main() {
-  runApp(new Dots(child: new Center(child: new Text('Touch me!'))));
+  runApp(new Dots(child: const Center(child: const Text('Touch me!'))));
 }

diff --git a/examples/layers/widgets/gestures.dart b/examples/layers/widgets/gestures.dart
index 2bc7015..deee29e 100644
--- a/examples/layers/widgets/gestures.dart
+++ b/examples/layers/widgets/gestures.dart

@@ -188,7 +188,7 @@
                         value: _scaleEnabled,
                         onChanged: (bool value) { setState(() { _scaleEnabled = value; }); }
                       ),
-                      new Text('Scale'),
+                      const Text('Scale'),
                     ]
                   ),
                   new Row(
@@ -197,7 +197,7 @@
                         value: _tapEnabled,
                         onChanged: (bool value) { setState(() { _tapEnabled = value; }); }
                       ),
-                      new Text('Tap'),
+                      const Text('Tap'),
                     ]
                   ),
                   new Row(
@@ -206,7 +206,7 @@
                         value: _doubleTapEnabled,
                         onChanged: (bool value) { setState(() { _doubleTapEnabled = value; }); }
                       ),
-                      new Text('Double Tap'),
+                      const Text('Double Tap'),
                     ]
                   ),
                   new Row(
@@ -215,7 +215,7 @@
                         value: _longPressEnabled,
                         onChanged: (bool value) { setState(() { _longPressEnabled = value; }); }
                       ),
-                      new Text('Long Press'),
+                      const Text('Long Press'),
                     ]
                   ),
                 ],
@@ -233,7 +233,7 @@
   runApp(new MaterialApp(
     theme: new ThemeData.dark(),
     home: new Scaffold(
-      appBar: new AppBar(title: new Text('Gestures Demo')),
+      appBar: new AppBar(title: const Text('Gestures Demo')),
       body: new GestureDemo()
     )
   ));

diff --git a/examples/layers/widgets/hello_world.dart b/examples/layers/widgets/hello_world.dart
index fc37338..1ad8675 100644
--- a/examples/layers/widgets/hello_world.dart
+++ b/examples/layers/widgets/hello_world.dart

@@ -4,4 +4,4 @@
 
 import 'package:flutter/widgets.dart';
 
-void main() => runApp(new Center(child: new Text('Hello, world!')));
+void main() => runApp(const Center(child: const Text('Hello, world!')));

diff --git a/examples/layers/widgets/media_query.dart b/examples/layers/widgets/media_query.dart
index 1158376..5a638dd 100644
--- a/examples/layers/widgets/media_query.dart
+++ b/examples/layers/widgets/media_query.dart

@@ -51,8 +51,8 @@
                 new Expanded(
                   child: new Text(name)
                 ),
-                new IconButton(
-                  icon: new Icon(Icons.more_vert),
+                const IconButton(
+                  icon: const Icon(Icons.more_vert),
                   onPressed: null
                 )
               ]
@@ -103,7 +103,7 @@
     title: 'Media Query Example',
     home: new Scaffold(
       appBar: new AppBar(
-        title: new Text('Media Query Example')
+        title: const Text('Media Query Example')
       ),
       body: new Material(child: new AdaptiveContainer(names: _kNames))
     )

diff --git a/examples/layers/widgets/sectors.dart b/examples/layers/widgets/sectors.dart
index 060b087..c978218 100644
--- a/examples/layers/widgets/sectors.dart
+++ b/examples/layers/widgets/sectors.dart

@@ -106,7 +106,7 @@
                         margin: const EdgeInsets.only(right: 10.0),
                         child: new WidgetToRenderBoxAdapter(renderBox: sectorAddIcon)
                       ),
-                      new Text('ADD SECTOR'),
+                      const Text('ADD SECTOR'),
                     ]
                   )
                 )
@@ -121,7 +121,7 @@
                         margin: const EdgeInsets.only(right: 10.0),
                         child: new WidgetToRenderBoxAdapter(renderBox: sectorRemoveIcon)
                       ),
-                      new Text('REMOVE SECTOR'),
+                      const Text('REMOVE SECTOR'),
                     ]
                   )
                 )
@@ -155,7 +155,7 @@
       title: 'Sector Layout',
       home: new Scaffold(
         appBar: new AppBar(
-          title: new Text('Sector Layout in a Widget Tree')
+          title: const Text('Sector Layout in a Widget Tree')
         ),
         body: buildBody()
       )

diff --git a/examples/layers/widgets/spinning_mixed.dart b/examples/layers/widgets/spinning_mixed.dart
index eb0aae3..0ffefaf 100644
--- a/examples/layers/widgets/spinning_mixed.dart
+++ b/examples/layers/widgets/spinning_mixed.dart

@@ -52,7 +52,7 @@
                     child: new Row(
                       children: <Widget>[
                         new Image.network('https://flutter.io/images/favicon.png'),
-                        new Text('PRESS ME'),
+                        const Text('PRESS ME'),
                       ]
                     ),
                     onPressed: () {

diff --git a/examples/layers/widgets/styled_text.dart b/examples/layers/widgets/styled_text.dart
index e151da3..917bc0e 100644
--- a/examples/layers/widgets/styled_text.dart
+++ b/examples/layers/widgets/styled_text.dart

@@ -124,7 +124,7 @@
     theme: new ThemeData.light(),
     home: new Scaffold(
       appBar: new AppBar(
-        title: new Text('Hal and Dave')
+        title: const Text('Hal and Dave')
       ),
       body: new Material(
         color: Colors.grey.shade50,