Add @override annotation to known overriden methods

sky/sdk/lib/rendering/paragraph.dart

Index: sky/sdk/lib/rendering/paragraph.dart
diff --git a/sky/sdk/lib/rendering/paragraph.dart b/sky/sdk/lib/rendering/paragraph.dart
index 605e0950f7b117c6d1140ed5158dd44b1800465e..23c3d6e6ef4a934e4d21ccbc92d3026bab034138 100644
--- a/sky/sdk/lib/rendering/paragraph.dart
+++ b/sky/sdk/lib/rendering/paragraph.dart
@@ -10,6 +10,7 @@ import '../painting/text_style.dart';
 
 abstract class InlineBase {
   sky.Node _toDOM(sky.Document owner);
+  @override
   String toString([String prefix = '']);
 }
 
@@ -20,13 +21,18 @@ class InlineText extends InlineBase {
 
   final String text;
 
+  @override
   sky.Node _toDOM(sky.Document owner) {
     return owner.createText(text);
   }
 
+  @override
   bool operator ==(other) => other is InlineText && text == other.text;
+
+  @override
   int get hashCode => text.hashCode;
 
+  @override
   String toString([String prefix = '']) => '${prefix}InlineText: "${text}"';
 }
 
@@ -39,6 +45,7 @@ class InlineStyle extends InlineBase {
   final TextStyle style;
   final List<InlineBase> children;
 
+  @override
   sky.Node _toDOM(sky.Document owner) {
     sky.Element parent = owner.createElement('t');
     style.applyToCSSStyle(parent.style);
@@ -48,6 +55,7 @@ class InlineStyle extends InlineBase {
     return parent;
   }
 
+  @override
   bool operator ==(other) {
     if (identical(this, other))
       return true;
@@ -62,6 +70,7 @@ class InlineStyle extends InlineBase {
     return true;
   }
 
+  @override
   int get hashCode {
     int value = 373;
     value = 37 * value + style.hashCode;
@@ -70,6 +79,7 @@ class InlineStyle extends InlineBase {
     return value;
   }
 
+  @override
   String toString([String prefix = '']) {
     List<String> result = [];
     result.add('${prefix}InlineStyle:');
@@ -128,12 +138,14 @@ class RenderParagraph extends RenderBox {
     _constraintsForCurrentLayout = constraints;
   }
 
+  @override
   double getMinIntrinsicWidth(BoxConstraints constraints) {
     _layout(constraints);
     return constraints.constrainWidth(
         _applyFloatingPointHack(_layoutRoot.rootElement.minContentWidth));
   }
 
+  @override
   double getMaxIntrinsicWidth(BoxConstraints constraints) {
     _layout(constraints);
     return constraints.constrainWidth(
@@ -146,14 +158,17 @@ class RenderParagraph extends RenderBox {
         _applyFloatingPointHack(_layoutRoot.rootElement.height));
   }
 
+  @override
   double getMinIntrinsicHeight(BoxConstraints constraints) {
     return _getIntrinsicHeight(constraints);
   }
 
+  @override
   double getMaxIntrinsicHeight(BoxConstraints constraints) {
     return _getIntrinsicHeight(constraints);
   }
 
+  @override
   double computeDistanceToActualBaseline(TextBaseline baseline) {
     assert(!needsLayout);
     _layout(constraints);
@@ -164,6 +179,7 @@ class RenderParagraph extends RenderBox {
     }
   }
 
+  @override
   void performLayout() {
     _layout(constraints);
     sky.Element root = _layoutRoot.rootElement;
@@ -172,6 +188,7 @@ class RenderParagraph extends RenderBox {
                                           _applyFloatingPointHack(root.height)));
   }
 
+  @override
   void paint(PaintingCanvas canvas, Offset offset) {
     // Ideally we could compute the min/max intrinsic width/height with a
     // non-destructive operation. However, currently, computing these values
@@ -189,7 +206,7 @@ class RenderParagraph extends RenderBox {
   }
 
   // we should probably expose a way to do precise (inter-glpyh) hit testing
-
+  @override
   String debugDescribeSettings(String prefix) {
     String result = '${super.debugDescribeSettings(prefix)}';
     result += '${prefix}inline:\n${inline.toString("$prefix  ")}\n';