Add |constraints| to Container for PopupMenuItem

This CL is the first step towards getting PopupMenuItem working in fn2. We
introduce the ability to add a minWidth to a Container by creating a
RenderConstrainedBox class to apply the new constraints.

R=ianh@google.com

Review URL: https://codereview.chromium.org/1155683011

sdk/lib/framework/components2/popup_menu_item.dart

@@ -6,21 +6,17 @@ import '../fn2.dart';
 import 'ink_well.dart';
 
 class PopupMenuItem extends Component {
-  static final Style _style = new Style('''
-    min-width: 112px;
-    padding: 16px;''');
-
   List<UINode> children;
   double opacity;
 
   PopupMenuItem({ Object key, this.children, this.opacity}) : super(key: key);
 
   UINode build() {
-    return new StyleNode(
-      new InkWell(
-        inlineStyle: opacity == null ? null : 'opacity: ${opacity}',
-        children: children
-      ),
-      _style);
+    return new Container(
+      constraints: const BoxConstraints(minWidth: 112.0),
+      padding: const EdgeDims.all(16.0),
+      // TODO(abarth): opacity: opacity,
+      child: new InkWell(children: children)
+    );
   }
 }

sdk/lib/framework/fn2.dart

@@ -18,7 +18,7 @@ import 'rendering/object.dart';
 import 'rendering/paragraph.dart';
 import 'rendering/stack.dart';
 export 'rendering/object.dart' show Point, Size, Rect, Color, Paint, Path;
-export 'rendering/box.dart' show BoxDecoration, Border, BorderSide, EdgeDims;
+export 'rendering/box.dart' show BoxConstraints, BoxDecoration, Border, BorderSide, EdgeDims;
 export 'rendering/flex.dart' show FlexDirection;
 
 // final sky.Tracing _tracing = sky.window.tracing;
@@ -421,6 +421,21 @@ class SizedBox extends OneChildRenderObjectWrapper {
   }
 }
 
+class ConstrainedBox extends OneChildRenderObjectWrapper {
+  RenderConstrainedBox root;
+  final BoxConstraints constraints;
+
+  ConstrainedBox({ this.constraints, UINode child, Object key })
+    : super(child: child, key: key);
+
+  RenderConstrainedBox createNode() => new RenderConstrainedBox(additionalConstraints: constraints);
+
+  void syncRenderObject(ConstrainedBox old) {
+    super.syncRenderObject(old);
+    root.additionalConstraints = constraints;
+  }
+}
+
 class Transform extends OneChildRenderObjectWrapper {
   RenderTransform root;
   final Matrix4 transform;
@@ -935,20 +950,22 @@ abstract class Component extends UINode {
 
 class Container extends Component {
   final UINode child;
-  final Matrix4 transform;
-  final EdgeDims margin;
+  final BoxConstraints constraints;
   final BoxDecoration decoration;
-  final Size desiredSize;
+  final EdgeDims margin;
   final EdgeDims padding;
+  final Matrix4 transform;
+  final Size desiredSize;
 
   Container({
     Object key,
     this.child,
-    this.transform,
-    this.margin,
+    this.constraints,
     this.decoration,
     this.desiredSize,
-    this.padding
+    this.margin,
+    this.padding,
+    this.transform
   }) : super(key: key);
 
   UINode build() {
@@ -963,6 +980,9 @@ class Container extends Component {
     if (desiredSize != null)
       current = new SizedBox(desiredSize: desiredSize, child: current);
 
+    if (constraints != null)
+      current = new ConstrainedBox(constraints: constraints);
+
     if (margin != null)
       current = new Padding(padding: margin, child: current);
 

sdk/lib/framework/rendering/box.dart

@@ -77,6 +77,14 @@ class BoxConstraints {
     );
   }
 
+  BoxConstraints apply(BoxConstraints constraints) {
+    return new BoxConstraints(
+      minWidth: math.max(minWidth, constraints.minWidth),
+      maxWidth: math.min(maxWidth, constraints.maxWidth),
+      minHeight: math.max(minHeight, constraints.minHeight),
+      maxHeight: math.min(maxHeight, constraints.maxHeight));
+  }
+
   final double minWidth;
   final double maxWidth;
   final double minHeight;
@@ -192,9 +200,8 @@ class RenderSizedBox extends RenderProxyBox {
   RenderSizedBox({
     RenderBox child,
     Size desiredSize: Size.infinite
-  }) : super(child) {
+  }) : super(child), _desiredSize = desiredSize {
     assert(desiredSize != null);
-    this.desiredSize = desiredSize;
   }
 
   Size _desiredSize;
@@ -220,6 +227,42 @@ class RenderSizedBox extends RenderProxyBox {
   String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}desiredSize: ${desiredSize}\n';
 }
 
+class RenderConstrainedBox extends RenderProxyBox {
+  RenderConstrainedBox({
+    RenderBox child,
+    BoxConstraints additionalConstraints
+  }) : super(child), _additionalConstraints = additionalConstraints {
+    assert(additionalConstraints != null);
+  }
+
+  BoxConstraints _additionalConstraints;
+  BoxConstraints get additionalConstraints => _additionalConstraints;
+  void set additionalConstraints (BoxConstraints value) {
+    assert(value != null);
+    if (_additionalConstraints == value)
+      return;
+    _additionalConstraints = value;
+    markNeedsLayout();
+  }
+
+  Size getIntrinsicDimensions(BoxConstraints constraints) {
+    if (child == null)
+      return constraints.constrain(Size.zero);
+    return child.getIntrinsicDimensions(constraints.apply(_additionalConstraints));
+  }
+
+  void performLayout() {
+    if (child != null) {
+      child.layout(constraints.apply(_additionalConstraints));
+      size = child.size;
+    } else {
+      performResize();
+    }
+  }
+
+  String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}additionalConstraints: ${additionalConstraints}\n';
+}
+
 class RenderClip extends RenderProxyBox {
   RenderClip({ RenderBox child }) : super(child);