[Effen] Start removing 'position'.

This creates a new RenderNode class that does positioning.
It then creates an fn Container class that uses it just to position things at 0,0 at the full extent of the container.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1128103009

framework/components/drawer.dart

@@ -97,22 +97,13 @@ class Drawer extends AnimatedComponent {
 
   static final Style _maskStyle = new Style('''
     background-color: black;
-    will-change: opacity;
-    position: absolute;
-    top: 0;
-    left: 0;
-    bottom: 0;
-    right: 0;'''
+    will-change: opacity;'''
   );
 
   static final Style _contentStyle = new Style('''
     background-color: ${Grey[50]};
     will-change: transform;
-    position: absolute;
-    width: ${_kWidth}px;
-    top: 0;
-    left: 0;
-    bottom: 0;'''
+    width: ${_kWidth}px;'''
   );
 
   List<UINode> children;
@@ -152,7 +143,7 @@ class Drawer extends AnimatedComponent {
       level: level);
 
     return new EventListenerNode(
-      new Container(
+      new FillStackContainer(
         style: _style,
         children: [ mask, content ]
       ),

framework/fn.dart

@@ -593,6 +593,42 @@ class FlexContainer extends SkyElementWrapper {
   }
 }
 
+class FillStackContainer extends SkyElementWrapper {
+
+  RenderCSSStack _root;
+  RenderCSSStack _createNode() => new RenderCSSStack(this);
+
+  static final FillStackContainer _emptyContainer = new FillStackContainer();
+
+  SkyNodeWrapper get _emptyNode => _emptyContainer;
+
+  FillStackContainer({
+    Object key,
+    List<UINode> children,
+    Style style,
+    String inlineStyle
+  }) : super(
+    key: key,
+    children: _positionNodesToFill(children),
+    style: style,
+    inlineStyle: inlineStyle
+  );
+
+  static StackParentData _fillParentData = new StackParentData()
+                                                 ..top = 0.0
+                                                 ..left = 0.0
+                                                 ..right = 0.0
+                                                 ..bottom = 0.0;
+
+  static List<UINode> _positionNodesToFill(List<UINode> input) {
+    if (input == null)
+      return null;
+    return input.map((node) {
+      return new ParentDataNode(node, _fillParentData);
+    }).toList();
+  }
+}
+
 class TextFragment extends SkyElementWrapper {
 
   RenderCSSInline _root;

framework/layout.dart

@@ -398,6 +398,63 @@ class RenderCSSFlex extends RenderCSSContainer {
 
 }
 
+class StackParentData extends CSSParentData {
+  double top;
+  double left;
+  double right;
+  double bottom;
+  void merge(StackParentData other) {
+    if (other.top != null)
+      top = other.top;
+    if (other.left != null)
+      left = other.left;
+    if (other.right != null)
+      right = other.right;
+    if (other.bottom != null)
+      bottom = other.bottom;
+    super.merge(other);
+  }
+}
+
+class RenderCSSStack extends RenderCSSContainer {
+
+  RenderCSSStack(debug) : super(debug);
+
+  void setupPos(RenderNode child) {
+    if (child.parentData is! StackParentData)
+      child.parentData = new StackParentData();
+  }
+
+  static final Style _displayPosition = new Style._addToCache('transform:translateX(0);position:relative');
+
+  String stylesToClasses(List<Style> styles) {
+    return super.stylesToClasses(styles) + ' ' + _displayPosition._className;
+  }
+
+  void markNeedsLayout() {
+    super.markNeedsLayout();
+
+    // pretend we did the layout:
+    RenderCSS child = _firstChild;
+    while (child != null) {
+      assert(child.parentData is StackParentData);
+      var style = 'position:absolute;';
+      if (child.parentData.top != null)
+        style += 'top:${child.parentData.top};';
+      if (child.parentData.left != null)
+        style += 'left:${child.parentData.left};';
+      if (child.parentData.right != null)
+        style += 'right:${child.parentData.right};';
+      if (child.parentData.bottom != null)
+        style += 'bottom:${child.parentData.bottom};';
+      child._additionalStylesFromParent = style;
+      child._updateInlineStyleAttribute();
+      child = child.parentData.nextSibling;
+    }
+  }
+
+}
+
 class RenderCSSParagraph extends RenderCSSContainer {
 
   RenderCSSParagraph(debug) : super(debug);