Rename Icon's type paramter to icon

The name of the parameter wasn't consistent with IconButton or DrawerItem, etc.

Fixes #1871

examples/address_book/lib/main.dart

@@ -20,7 +20,7 @@ class Field extends StatelessComponent {
     return new Row(<Widget>[
         new Padding(
           padding: const EdgeDims.symmetric(horizontal: 16.0),
-          child: new Icon(type: icon)
+          child: new Icon(icon: icon)
         ),
         new Flexible(
           child: new Input(
@@ -43,7 +43,7 @@ class AddressBookHome extends StatelessComponent {
 
   Widget buildFloatingActionButton(BuildContext context) {
     return new FloatingActionButton(
-      child: new Icon(type: 'image/photo_camera'),
+      child: new Icon(icon: 'image/photo_camera'),
       backgroundColor: Theme.of(context).accentColor
     );
   }

examples/fitness/lib/feed.dart

@@ -200,7 +200,7 @@ class FeedFragmentState extends State<FeedFragment> {
     switch (_fitnessMode) {
       case FitnessMode.feed:
         return new FloatingActionButton(
-          child: new Icon(type: 'content/add'),
+          child: new Icon(icon: 'content/add'),
           onPressed: _handleActionButtonPressed
         );
       case FitnessMode.chart:

examples/stocks/lib/stock_home.dart

@@ -252,7 +252,7 @@ class StockHomeState extends State<StockHome> {
 
   Widget buildFloatingActionButton() {
     return new FloatingActionButton(
-      child: new Icon(type: 'content/add'),
+      child: new Icon(icon: 'content/add'),
       backgroundColor: Colors.redAccent[200],
       onPressed: _handleStockPurchased
     );

examples/stocks/lib/stock_menu.dart

@@ -62,7 +62,7 @@ Future showStockMenu({BuildContext context, bool autorefresh, ValueChanged<bool>
             new FlatButton(
               child: new Row(<Widget>[
                 new Icon(
-                  type: 'device/dvr',
+                  icon: 'device/dvr',
                   size: IconSize.s18
                 ),
                 new Container(

examples/widgets/card_collection.dart

@@ -329,11 +329,11 @@ class CardCollectionState extends State<CardCollection> {
         backgroundMessage = "Unsupported dismissDirection";
     }
 
-    Widget leftArrowIcon =  new Icon(type: 'navigation/arrow_back', size: IconSize.s36);
+    Widget leftArrowIcon =  new Icon(icon: 'navigation/arrow_back', size: IconSize.s36);
     if (_dismissDirection == DismissDirection.right)
       leftArrowIcon = new Opacity(opacity: 0.1, child: leftArrowIcon);
 
-    Widget rightArrowIcon =  new Icon(type: 'navigation/arrow_forward', size: IconSize.s36);
+    Widget rightArrowIcon =  new Icon(icon: 'navigation/arrow_forward', size: IconSize.s36);
     if (_dismissDirection == DismissDirection.left)
       rightArrowIcon = new Opacity(opacity: 0.1, child: rightArrowIcon);
 

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

@@ -48,7 +48,7 @@ class DrawerItem extends StatelessComponent {
         new Padding(
           padding: const EdgeDims.symmetric(horizontal: 16.0),
           child: new Icon(
-            type: icon,
+            icon: icon,
             colorFilter: _getColorFilter(themeData)
           )
         )

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

@@ -223,7 +223,7 @@ class DropdownButton<T> extends StatelessComponent {
               alignment: const FractionalOffset(0.5, 0.0)
             ),
             new Container(
-              child: new Icon(type: 'navigation/arrow_drop_down', size: IconSize.s36),
+              child: new Icon(icon: 'navigation/arrow_drop_down', size: IconSize.s36),
               padding: const EdgeDims.only(top: 6.0)
             )
           ])

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

@@ -26,16 +26,16 @@ class Icon extends StatelessComponent {
   Icon({
     Key key,
     this.size: IconSize.s24,
-    this.type: '',
+    this.icon: '',
     this.color,
     this.colorFilter
   }) : super(key: key) {
     assert(size != null);
-    assert(type != null);
+    assert(icon != null);
   }
 
   final IconSize size;
-  final String type;
+  final String icon;
   final IconThemeColor color;
   final ColorFilter colorFilter;
 
@@ -60,7 +60,7 @@ class Icon extends StatelessComponent {
   Widget build(BuildContext context) {
     String category = '';
     String subtype = '';
-    List<String> parts = type.split('/');
+    List<String> parts = icon.split('/');
     if (parts.length == 2) {
       category = parts[0];
       subtype = parts[1];
@@ -80,7 +80,7 @@ class Icon extends StatelessComponent {
 
   void debugFillDescription(List<String> description) {
     super.debugFillDescription(description);
-    description.add('$type');
+    description.add('$icon');
     description.add('size: $size');
   }
 }

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

@@ -27,7 +27,7 @@ class IconButton extends StatelessComponent {
       child: new Padding(
         padding: const EdgeDims.all(8.0),
         child: new Icon(
-          type: icon,
+          icon: icon,
           color: color,
           colorFilter: colorFilter
         )

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

@@ -320,7 +320,7 @@ class Tab extends StatelessComponent {
     assert(label.icon != null);
     Color iconColor = selected ? selectedColor : color;
     ColorFilter filter = new ColorFilter.mode(iconColor, TransferMode.srcATop);
-    return new Icon(type: label.icon, colorFilter: filter);
+    return new Icon(icon: label.icon, colorFilter: filter);
   }
 
   Widget build(BuildContext context) {