Upgrading samples to flutter_lints, part 1 of n (#804)

isolate_example/lib/data_transfer_page.dart

@@ -43,7 +43,7 @@ class DataTransferPage extends StatelessWidget {
               'Number Generator Progress',
               style: Theme.of(context).textTheme.headline6,
             ),
-            padding: EdgeInsets.all(8),
+            padding: const EdgeInsets.all(8),
           ),
           LinearProgressIndicator(
             value: controller.progressPercent,
@@ -213,7 +213,7 @@ class RunningList extends StatelessWidget {
                 ),
                 color: Colors.lightGreenAccent,
               ),
-              Divider(
+              const Divider(
                 color: Colors.blue,
                 height: 3,
               ),

isolate_example/lib/infinite_process_page.dart

@@ -76,7 +76,7 @@ class InfiniteProcessPage extends StatelessWidget {
                     inactiveTrackColor: Colors.deepOrangeAccent,
                     inactiveThumbColor: Colors.black,
                   ),
-                  Text('Pause/Resume'),
+                  const Text('Pause/Resume'),
                 ],
               ),
               Row(
@@ -207,7 +207,7 @@ class RunningList extends StatelessWidget {
                     ? Colors.lightGreenAccent
                     : Colors.deepOrangeAccent,
               ),
-              Divider(
+              const Divider(
                 color: Colors.blue,
                 height: 3,
               ),

isolate_example/lib/main.dart

@@ -34,7 +34,7 @@ class HomePage extends StatelessWidget {
         length: 3,
         child: Scaffold(
           appBar: AppBar(
-            bottom: TabBar(
+            bottom: const TabBar(
               tabs: [
                 Tab(
                   icon: Icon(Icons.flash_on),
@@ -50,7 +50,7 @@ class HomePage extends StatelessWidget {
                 ),
               ],
             ),
-            title: Text('Isolate Example'),
+            title: const Text('Isolate Example'),
           ),
           body: TabBarView(
             children: [

isolate_example/lib/performance_page.dart

@@ -46,7 +46,7 @@ class _PerformancePageState extends State<PerformancePage> {
           SmoothAnimationWidget(),
           Container(
             alignment: Alignment.bottomCenter,
-            padding: EdgeInsets.only(top: 150),
+            padding: const EdgeInsets.only(top: 150),
             child: Column(
               children: [
                 FutureBuilder(
@@ -85,7 +85,7 @@ class _PerformancePageState extends State<PerformancePage> {
   void handleComputeOnMain(BuildContext context) {
     var future = computeOnMainIsolate()
       ..then((_) {
-        var snackBar = SnackBar(
+        var snackBar = const SnackBar(
           content: Text('Main Isolate Done!'),
         );
         ScaffoldMessenger.of(context).showSnackBar(snackBar);
@@ -99,7 +99,7 @@ class _PerformancePageState extends State<PerformancePage> {
   void handleComputeOnSecondary(BuildContext context) {
     var future = computeOnSecondaryIsolate()
       ..then((_) {
-        var snackBar = SnackBar(
+        var snackBar = const SnackBar(
           content: Text('Secondary Isolate Done!'),
         );
         ScaffoldMessenger.of(context).showSnackBar(snackBar);
@@ -114,7 +114,7 @@ class _PerformancePageState extends State<PerformancePage> {
     // A delay is added here to give Flutter the chance to redraw the UI at
     // least once before the computation (which, since it's run on the main
     // isolate, will lock up the app) begins executing.
-    await Future<void>.delayed(Duration(milliseconds: 100));
+    await Future<void>.delayed(const Duration(milliseconds: 100));
     fib(45);
   }
 
@@ -156,14 +156,14 @@ class SmoothAnimationWidgetState extends State<SmoothAnimationWidget>
         animation: _borderAnimation,
         builder: (context, child) {
           return Container(
-            child: FlutterLogo(
+            child: const FlutterLogo(
               size: 200,
             ),
             alignment: Alignment.bottomCenter,
             width: 350,
             height: 200,
             decoration: BoxDecoration(
-              gradient: LinearGradient(
+              gradient: const LinearGradient(
                 begin: Alignment.topLeft,
                 colors: [
                   Colors.blueAccent,