Fix the Sky tests

Instead of triggering layout synchronously during AppView construction, we now
schedule the initial layout using a magic bootstrapping function.

TBR=ianh@google.com

Review URL: https://codereview.chromium.org/1172123003.

sdk/lib/framework/app.dart

@@ -25,7 +25,7 @@ class AppView {
     _renderView = new RenderView(child: root);
     _renderView.attach();
     _renderView.rootConstraints = _viewConstraints;
-    _renderView.layout(_renderView.rootConstraints);
+    _renderView.scheduleInitialLayout();
   }
 
   RenderView _renderView;

sdk/lib/framework/rendering/box.dart

@@ -956,8 +956,6 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
     markNeedsLayout();
   }
 
-  ViewConstraints get constraints => super.constraints as ViewConstraints;
-
   void performLayout() {
     if (_rootConstraints.orientation != _orientation) {
       if (_orientation != null && child != null)

sdk/lib/framework/rendering/object.dart

@@ -119,6 +119,14 @@ abstract class RenderObject extends AbstractNode {
       scheduler.ensureVisualUpdate();
     }
   }
+  void scheduleInitialLayout() {
+    assert(attached);
+    assert(parent == null);
+    assert(_relayoutSubtreeRoot == null);
+    _relayoutSubtreeRoot = this;
+    _nodesNeedingLayout.add(this);
+    scheduler.ensureVisualUpdate();
+  }
   static void flushLayout() {
     _debugDoingLayout = true;
     List<RenderObject> dirtyNodes = _nodesNeedingLayout;

tests/raw/padding_deflate.dart

@@ -7,6 +7,7 @@ import '../resources/third_party/unittest/unittest.dart';
 import '../resources/unit.dart';
 import '../resources/display_list.dart';
 import 'package:sky/framework/rendering/box.dart';
+import 'package:sky/framework/rendering/object.dart';
 
 void main() {
   initUnit();
@@ -22,7 +23,10 @@ void main() {
       child: paddingBox
     );
     TestView renderView = new TestView(child: root);
-    renderView.layout(new ViewConstraints(width: sky.view.width, height: sky.view.height));
+    renderView.attach();
+    renderView.rootConstraints = new ViewConstraints(width: sky.view.width, height: sky.view.height);
+    renderView.scheduleInitialLayout();
+    RenderObject.flushLayout();
     expect(coloredBox.size.width, equals(sky.view.width - 20));
     expect(coloredBox.size.height, equals(sky.view.height - 20));
   });

tests/raw/render_box.dart

@@ -7,6 +7,7 @@ import '../resources/unit.dart';
 import '../resources/display_list.dart';
 import 'dart:sky' as sky;
 import 'package:sky/framework/rendering/box.dart';
+import 'package:sky/framework/rendering/object.dart';
 
 void main() {
   initUnit();
@@ -18,7 +19,10 @@ void main() {
       )
     );
     TestView renderView = new TestView(child: root);
-    renderView.layout(new ViewConstraints(width: sky.view.width, height: sky.view.height));
+    renderView.attach();
+    renderView.rootConstraints = new ViewConstraints(width: sky.view.width, height: sky.view.height);
+    renderView.scheduleInitialLayout();
+    RenderObject.flushLayout();
     expect(root.size.width, equals(sky.view.width));
     expect(root.size.height, equals(sky.view.height));
     renderView.paintFrame();

tests/resources/display_list.dart

@@ -125,7 +125,9 @@ class TestApp {
   TestApp(RenderBox root) {
     _renderView = new TestView(child: root);
     _renderView.attach();
-    _renderView.layout(new ViewConstraints(width: sky.view.width, height: sky.view.height));
+    _renderView.rootConstraints = new ViewConstraints(width: sky.view.width, height: sky.view.height);
+    _renderView.scheduleInitialLayout();
+    RenderObject.flushLayout();
     _renderView.paintFrame();
     print(_renderView.lastPaint); // TODO(ianh): figure out how to make this fit the unit testing framework better
   }