some whitespace cleanup (#14443)

diff --git a/examples/flutter_gallery/lib/demo/animation/home.dart b/examples/flutter_gallery/lib/demo/animation/home.dart
index a2fe95d..f8e8170 100644
--- a/examples/flutter_gallery/lib/demo/animation/home.dart
+++ b/examples/flutter_gallery/lib/demo/animation/home.dart
@@ -375,7 +375,7 @@
 
   @override
   _SnappingScrollPhysics applyTo(ScrollPhysics ancestor) {
-    return new _SnappingScrollPhysics(parent: buildParent(ancestor),  midScrollOffset: midScrollOffset);
+    return new _SnappingScrollPhysics(parent: buildParent(ancestor), midScrollOffset: midScrollOffset);
   }
 
   Simulation _toMidScrollOffsetSimulation(double offset, double dragVelocity) {
@@ -411,7 +411,7 @@
       // snap to midScrollOffset if they're more than halfway there,
       // otherwise snap to zero.
       final double snapThreshold = midScrollOffset / 2.0;
-      if (offset >=  snapThreshold && offset < midScrollOffset)
+      if (offset >= snapThreshold && offset < midScrollOffset)
         return _toMidScrollOffsetSimulation(offset, dragVelocity);
       if (offset > 0.0 && offset < snapThreshold)
         return _toZeroScrollOffsetSimulation(offset, dragVelocity);
diff --git a/examples/flutter_gallery/lib/demo/colors_demo.dart b/examples/flutter_gallery/lib/demo/colors_demo.dart
index 4693a60..b3e9e99 100644
--- a/examples/flutter_gallery/lib/demo/colors_demo.dart
+++ b/examples/flutter_gallery/lib/demo/colors_demo.dart
@@ -97,7 +97,7 @@
     final TextTheme textTheme = Theme.of(context).textTheme;
     final TextStyle whiteTextStyle = textTheme.body1.copyWith(color: Colors.white);
     final TextStyle blackTextStyle = textTheme.body1.copyWith(color: Colors.black);
-    final List<Widget> colorItems =  primaryKeys.map((int index) {
+    final List<Widget> colorItems = primaryKeys.map((int index) {
       return new DefaultTextStyle(
         style: index > colors.threshold ? whiteTextStyle : blackTextStyle,
         child: new ColorItem(index: index, color: colors.primary[index]),
diff --git a/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart b/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart
index 9990dc7..b452371 100644
--- a/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart
+++ b/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart
@@ -30,10 +30,10 @@
 
 class CupertinoNavigationDemo extends StatelessWidget {
   CupertinoNavigationDemo()
-      : colorItems = new List<Color>.generate(50, (int index){
+      : colorItems = new List<Color>.generate(50, (int index) {
           return coolColors[new math.Random().nextInt(coolColors.length)];
         }) ,
-        colorNameItems = new List<String>.generate(50, (int index){
+        colorNameItems = new List<String>.generate(50, (int index) {
           return coolColorNames[new math.Random().nextInt(coolColorNames.length)];
         });
 
diff --git a/examples/flutter_gallery/lib/demo/cupertino/cupertino_switch_demo.dart b/examples/flutter_gallery/lib/demo/cupertino/cupertino_switch_demo.dart
index c666156..8c62569 100644
--- a/examples/flutter_gallery/lib/demo/cupertino/cupertino_switch_demo.dart
+++ b/examples/flutter_gallery/lib/demo/cupertino/cupertino_switch_demo.dart
@@ -23,7 +23,7 @@
         title: const Text('Cupertino Switch'),
       ),
       body: new Center(
-        child:  new CupertinoSwitch(
+        child: new CupertinoSwitch(
           value: _switchValue,
           onChanged: (bool value) {
             setState(() {
diff --git a/examples/flutter_gallery/lib/demo/material/drawer_demo.dart b/examples/flutter_gallery/lib/demo/material/drawer_demo.dart
index 8d96bd5..54f6f35 100644
--- a/examples/flutter_gallery/lib/demo/material/drawer_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/drawer_demo.dart
@@ -100,7 +100,7 @@
                   package: _kGalleryAssetsPackage,
                 ),
               ),
-              otherAccountsPictures:  <Widget>[
+              otherAccountsPictures: <Widget>[
                 new GestureDetector(
                   onTap: () {
                     _onOtherAccountsTap(context);
diff --git a/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart b/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart
index 2fb695a..53d3ae9 100644
--- a/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart
@@ -53,7 +53,7 @@
     });
   }
 
-  void _showMessage()  {
+  void _showMessage() {
     showDialog<Null>(
       context: context,
       child: new AlertDialog(
diff --git a/examples/flutter_gallery/lib/demo/material/scrollable_tabs_demo.dart b/examples/flutter_gallery/lib/demo/material/scrollable_tabs_demo.dart
index 49f9958..6569b57 100644
--- a/examples/flutter_gallery/lib/demo/material/scrollable_tabs_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/scrollable_tabs_demo.dart
@@ -111,7 +111,7 @@
             child: new Container(
               key: new ObjectKey(page.icon),
               padding: const EdgeInsets.all(12.0),
-              child:new Card(
+              child: new Card(
                 child: new Center(
                   child: new Icon(
                     page.icon,
diff --git a/examples/flutter_gallery/lib/demo/material/text_form_field_demo.dart b/examples/flutter_gallery/lib/demo/material/text_form_field_demo.dart
index 8a4421f..b133f7d 100644
--- a/examples/flutter_gallery/lib/demo/material/text_form_field_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/text_form_field_demo.dart
@@ -42,7 +42,7 @@
   void _handleSubmitted() {
     final FormState form = _formKey.currentState;
     if (!form.validate()) {
-      _autovalidate = true;  // Start validating on every change.
+      _autovalidate = true; // Start validating on every change.
       showInSnackBar('Please fix the errors in red before submitting.');
     } else {
       form.save();
diff --git a/examples/flutter_gallery/lib/demo/pesto_demo.dart b/examples/flutter_gallery/lib/demo/pesto_demo.dart
index 1175f06..5dce4d0 100644
--- a/examples/flutter_gallery/lib/demo/pesto_demo.dart
+++ b/examples/flutter_gallery/lib/demo/pesto_demo.dart
@@ -18,7 +18,7 @@
 const String _kSmallLogoImage = 'pesto/logo_small.png';
 const String _kGalleryAssetsPackage = 'flutter_gallery_assets';
 const double _kAppBarHeight = 128.0;
-const double _kFabHalfSize = 28.0;  // TODO(mpcomplete): needs to adapt to screen size
+const double _kFabHalfSize = 28.0; // TODO(mpcomplete): needs to adapt to screen size
 const double _kRecipePageMaxWidth = 500.0;
 
 final Set<Recipe> _favoriteRecipes = new Set<Recipe>();
@@ -667,7 +667,7 @@
     author: 'Ali Connors',
     ingredientsImagePath: 'pesto/healthy.png',
     ingredientsImagePackage: _kGalleryAssetsPackage,
-    description: 'This dish is a terrific pairing to almost any main. Bonus- it’s quick, easy to make, and turns even the simplest of dishes into a delicacy. Sweet coconut cream will leave your mouth watering, with yummy caramelized  flecks of rice adding an extra bit of taste. Fluff with fork before serving for best results.',
+    description: 'This dish is a terrific pairing to almost any main. Bonus- it’s quick, easy to make, and turns even the simplest of dishes into a delicacy. Sweet coconut cream will leave your mouth watering, with yummy caramelized flecks of rice adding an extra bit of taste. Fluff with fork before serving for best results.',
     imagePath: 'pesto/image6.jpg',
     imagePackage: _kGalleryAssetsPackage,
     ingredients: const<RecipeIngredient>[
@@ -732,7 +732,7 @@
     imagePackage: _kGalleryAssetsPackage,
     ingredients: const<RecipeIngredient>[
       const RecipeIngredient(amount: '1', description: 'Small garlic clove, peeled'),
-      const RecipeIngredient(amount: '2', description: 'Whole  artichokes'),
+      const RecipeIngredient(amount: '2', description: 'Whole artichokes'),
       const RecipeIngredient(amount: '4 tbsp', description: 'Fresh lemon juice'),
       const RecipeIngredient(amount: '4 tbsp', description: 'Unsalted butter'),
       const RecipeIngredient(amount: '2 tbsp', description: 'Extra-virgin olive oil'),
@@ -748,7 +748,7 @@
     author: 'Trevor Hansen',
     ingredientsImagePath: 'pesto/veggie.png',
     ingredientsImagePackage: _kGalleryAssetsPackage,
-    description: 'Life is good when you add amazingly warm bread, fresh pesto sauce, and roasted tomatoes to the table. This a  classic starter to break out in a pinch. It’s easy to make and extra tasty.',
+    description: 'Life is good when you add amazingly warm bread, fresh pesto sauce, and roasted tomatoes to the table. This a classic starter to break out in a pinch. It’s easy to make and extra tasty.',
     imagePath: 'pesto/image10.jpg',
     imagePackage: _kGalleryAssetsPackage,
     ingredients: const<RecipeIngredient>[
@@ -771,7 +771,7 @@
     author: 'Sandra Adams',
     ingredientsImagePath: 'pesto/spicy.png',
     ingredientsImagePackage: _kGalleryAssetsPackage,
-    description: 'Great stir-fried bok choy starts at the market. For me, nothing says tasty like garlic and baby bok choy. Choose fresh, crisp greens. Once home, wash, chop, and then ready for the wok.  No family style spread is complete without these greens.',
+    description: 'Great stir-fried bok choy starts at the market. For me, nothing says tasty like garlic and baby bok choy. Choose fresh, crisp greens. Once home, wash, chop, and then ready for the wok. No family style spread is complete without these greens.',
     imagePath: 'pesto/image11.jpg',
     imagePackage: _kGalleryAssetsPackage,
     ingredients: const<RecipeIngredient>[
diff --git a/examples/flutter_gallery/lib/demo/shrine/shrine_data.dart b/examples/flutter_gallery/lib/demo/shrine/shrine_data.dart
index 1d1e0c9..46e2758 100644
--- a/examples/flutter_gallery/lib/demo/shrine/shrine_data.dart
+++ b/examples/flutter_gallery/lib/demo/shrine/shrine_data.dart
@@ -30,7 +30,7 @@
   avatarAsset: 'shrine/vendors/zach.jpg',
   avatarAssetPackage: _kGalleryAssetsPackage,
   description:
-    'Trevor makes great stuff for awesome people like you.  Super cool and extra '
+    'Trevor makes great stuff for awesome people like you. Super cool and extra '
     'awesome all of his shop’s goods are handmade with love. Custom orders are '
     'available upon request if you need something extra special.'
 );
@@ -40,7 +40,7 @@
   avatarAsset: 'shrine/vendors/peter-carlsson.png',
   avatarAssetPackage: _kGalleryAssetsPackage,
   description:
-    'Peter makes great stuff for awesome people like you.  Super cool and extra '
+    'Peter makes great stuff for awesome people like you. Super cool and extra '
     'awesome all of his shop’s goods are handmade with love. Custom orders are '
     'available upon request if you need something extra special.'
 );
diff --git a/examples/flutter_gallery/lib/gallery/syntax_highlighter.dart b/examples/flutter_gallery/lib/gallery/syntax_highlighter.dart
index 51b1215..63be2e7 100644
--- a/examples/flutter_gallery/lib/gallery/syntax_highlighter.dart
+++ b/examples/flutter_gallery/lib/gallery/syntax_highlighter.dart
@@ -109,7 +109,7 @@
       return new TextSpan(style: _style.baseStyle, children: formattedText);
     } else {
       // Parsing failed, return with only basic formatting
-      return new TextSpan(style:_style.baseStyle, text: src);
+      return new TextSpan(style: _style.baseStyle, text: src);
     }
   }