Provide the BuildContext to createRenderObject and updateRenderObject

We'll need this for RTL support because the RTL state will live in the widget
tree. Also, remove the `oldWidget` argument to updateRenderObject because there
aren't any clients for it.

examples/layers/widgets/custom_render_box.dart

@@ -37,7 +37,7 @@ class RenderDots extends RenderConstrainedBox {
 
 class Dots extends OneChildRenderObjectWidget {
   Dots({ Key key, Widget child }) : super(key: key, child: child);
-  RenderDots createRenderObject() => new RenderDots();
+  RenderDots createRenderObject(BuildContext context) => new RenderDots();
 }
 
 void main() {

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

@@ -67,14 +67,14 @@ class _CheckboxRenderObjectWidget extends LeafRenderObjectWidget {
   final Color inactiveColor;
   final ValueChanged<bool> onChanged;
 
-  _RenderCheckbox createRenderObject() => new _RenderCheckbox(
+  _RenderCheckbox createRenderObject(BuildContext context) => new _RenderCheckbox(
     value: value,
     activeColor: activeColor,
     inactiveColor: inactiveColor,
     onChanged: onChanged
   );
 
-  void updateRenderObject(_RenderCheckbox renderObject, _CheckboxRenderObjectWidget oldWidget) {
+  void updateRenderObject(BuildContext context, _RenderCheckbox renderObject) {
     renderObject
       ..value = value
       ..activeColor = activeColor

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

@@ -279,9 +279,9 @@ class InkFeatures extends OneChildRenderObjectWidget {
 
   final Color color;
 
-  RenderInkFeatures createRenderObject() => new RenderInkFeatures(color: color);
+  RenderInkFeatures createRenderObject(BuildContext context) => new RenderInkFeatures(color: color);
 
-  void updateRenderObject(RenderInkFeatures renderObject, InkFeatures oldWidget) {
+  void updateRenderObject(BuildContext context, RenderInkFeatures renderObject) {
     renderObject.color = color;
   }
 }

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

@@ -72,14 +72,14 @@ class _RadioRenderObjectWidget extends LeafRenderObjectWidget {
   final Color activeColor;
   final ValueChanged<bool> onChanged;
 
-  _RenderRadio createRenderObject() => new _RenderRadio(
+  _RenderRadio createRenderObject(BuildContext context) => new _RenderRadio(
     value: selected,
     activeColor: activeColor,
     inactiveColor: inactiveColor,
     onChanged: onChanged
   );
 
-  void updateRenderObject(_RenderRadio renderObject, _RadioRenderObjectWidget oldWidget) {
+  void updateRenderObject(BuildContext context, _RenderRadio renderObject) {
     renderObject
       ..value = selected
       ..activeColor = activeColor

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

@@ -55,13 +55,13 @@ class _SliderRenderObjectWidget extends LeafRenderObjectWidget {
   final Color activeColor;
   final ValueChanged<double> onChanged;
 
-  _RenderSlider createRenderObject() => new _RenderSlider(
+  _RenderSlider createRenderObject(BuildContext context) => new _RenderSlider(
     value: value,
     activeColor: activeColor,
     onChanged: onChanged
   );
 
-  void updateRenderObject(_RenderSlider renderObject, _SliderRenderObjectWidget oldWidget) {
+  void updateRenderObject(BuildContext context, _RenderSlider renderObject) {
     renderObject
       ..value = value
       ..activeColor = activeColor

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

@@ -68,7 +68,7 @@ class _SwitchRenderObjectWidget extends LeafRenderObjectWidget {
   final Color inactiveTrackColor;
   final ValueChanged<bool> onChanged;
 
-  _RenderSwitch createRenderObject() => new _RenderSwitch(
+  _RenderSwitch createRenderObject(BuildContext context) => new _RenderSwitch(
     value: value,
     activeColor: activeColor,
     inactiveColor: inactiveColor,
@@ -77,7 +77,7 @@ class _SwitchRenderObjectWidget extends LeafRenderObjectWidget {
     onChanged: onChanged
   );
 
-  void updateRenderObject(_RenderSwitch renderObject, _SwitchRenderObjectWidget oldWidget) {
+  void updateRenderObject(BuildContext context, _RenderSwitch renderObject) {
     renderObject
       ..value = value
       ..activeColor = activeColor

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

@@ -265,13 +265,13 @@ class _TabBarWrapper extends MultiChildRenderObjectWidget {
   final bool isScrollable;
   final TabLayoutChanged onLayoutChanged;
 
-  _RenderTabBar createRenderObject() {
+  _RenderTabBar createRenderObject(BuildContext context) {
     _RenderTabBar result = new _RenderTabBar(onLayoutChanged);
-    updateRenderObject(result, null);
+    updateRenderObject(context, result);
     return result;
   }
 
-  void updateRenderObject(_RenderTabBar renderObject, _TabBarWrapper oldWidget) {
+  void updateRenderObject(BuildContext context, _RenderTabBar renderObject) {
     renderObject
       ..selectedIndex = selectedIndex
       ..indicatorColor = indicatorColor

packages/flutter/lib/src/widgets/auto_layout.dart

@@ -19,9 +19,9 @@ class AutoLayout extends MultiChildRenderObjectWidget {
 
   final AutoLayoutDelegate delegate;
 
-  RenderAutoLayout createRenderObject() => new RenderAutoLayout(delegate: delegate);
+  RenderAutoLayout createRenderObject(BuildContext context) => new RenderAutoLayout(delegate: delegate);
 
-  void updateRenderObject(RenderAutoLayout renderObject, AutoLayout oldWidget) {
+  void updateRenderObject(BuildContext context, RenderAutoLayout renderObject) {
     renderObject.delegate = delegate;
   }
 }

packages/flutter/lib/src/widgets/binding.dart

@@ -192,9 +192,9 @@ class RenderObjectToWidgetAdapter<T extends RenderObject> extends RenderObjectWi
 
   RenderObjectToWidgetElement<T> createElement() => new RenderObjectToWidgetElement<T>(this);
 
-  RenderObjectWithChildMixin<T> createRenderObject() => container;
+  RenderObjectWithChildMixin<T> createRenderObject(BuildContext context) => container;
 
-  void updateRenderObject(RenderObject renderObject, RenderObjectWidget oldWidget) { }
+  void updateRenderObject(BuildContext context, RenderObject renderObject) { }
 
   RenderObjectToWidgetElement<T> attachToRenderTree([RenderObjectToWidgetElement<T> element]) {
     BuildableElement.lockState(() {

packages/flutter/lib/src/widgets/child_view.dart

@@ -32,9 +32,9 @@ class _ChildViewWidget extends LeafRenderObjectWidget {
   final ChildViewConnection child;
   final double scale;
 
-  RenderChildView createRenderObject() => new RenderChildView(child: child, scale: scale);
+  RenderChildView createRenderObject(BuildContext context) => new RenderChildView(child: child, scale: scale);
 
-  void updateRenderObject(RenderChildView renderObject, _ChildViewWidget oldWidget) {
+  void updateRenderObject(BuildContext context, RenderChildView renderObject) {
     renderObject
       ..child = child
       ..scale = scale;

packages/flutter/lib/src/widgets/editable.dart

@@ -365,7 +365,7 @@ class _EditableLineWidget extends LeafRenderObjectWidget {
   final Offset paintOffset;
   final ViewportDimensionsChangeCallback onPaintOffsetUpdateNeeded;
 
-  RenderEditableLine createRenderObject() {
+  RenderEditableLine createRenderObject(BuildContext context) {
     return new RenderEditableLine(
       text: _styledTextSpan,
       cursorColor: cursorColor,
@@ -378,8 +378,7 @@ class _EditableLineWidget extends LeafRenderObjectWidget {
     );
   }
 
-  void updateRenderObject(RenderEditableLine renderObject,
-                          _EditableLineWidget oldWidget) {
+  void updateRenderObject(BuildContext context, RenderEditableLine renderObject) {
     renderObject
       ..text = _styledTextSpan
       ..cursorColor = cursorColor

packages/flutter/lib/src/widgets/framework.dart

@@ -485,12 +485,12 @@ abstract class RenderObjectWidget extends Widget {
   /// Constructs an instance of the RenderObject class that this
   /// RenderObjectWidget represents, using the configuration described by this
   /// RenderObjectWidget.
-  RenderObject createRenderObject();
+  RenderObject createRenderObject(BuildContext context);
 
   /// Copies the configuration described by this RenderObjectWidget to the given
   /// RenderObject, which must be of the same type as returned by this class'
-  /// createRenderObject().
-  void updateRenderObject(RenderObject renderObject, RenderObjectWidget oldWidget) { }
+  /// createRenderObject(BuildContext context).
+  void updateRenderObject(BuildContext context, RenderObject renderObject) { }
 
   void didUnmountRenderObject(RenderObject renderObject) { }
 }
@@ -1033,7 +1033,7 @@ class ErrorWidget extends LeafRenderObjectWidget {
     } catch (e) { }
     return 'Error';
   }
-  RenderBox createRenderObject() => new RenderErrorBox(message);
+  RenderBox createRenderObject(BuildContext context) => new RenderErrorBox(message);
 }
 
 typedef void BuildScheduler(BuildableElement element);
@@ -1509,7 +1509,7 @@ abstract class RenderObjectElement<T extends RenderObjectWidget> extends Buildab
 
   void mount(Element parent, dynamic newSlot) {
     super.mount(parent, newSlot);
-    _renderObject = widget.createRenderObject();
+    _renderObject = widget.createRenderObject(this);
     assert(() { debugUpdateRenderObjectOwner(); return true; });
     assert(_slot == newSlot);
     attachRenderObject(newSlot);
@@ -1517,11 +1517,10 @@ abstract class RenderObjectElement<T extends RenderObjectWidget> extends Buildab
   }
 
   void update(T newWidget) {
-    T oldWidget = widget;
     super.update(newWidget);
     assert(widget == newWidget);
     assert(() { debugUpdateRenderObjectOwner(); return true; });
-    widget.updateRenderObject(renderObject, oldWidget);
+    widget.updateRenderObject(this, renderObject);
     _dirty = false;
   }
 

packages/flutter/lib/src/widgets/gesture_detector.dart

@@ -303,7 +303,7 @@ class RawGestureDetectorState extends State<RawGestureDetector> {
     if (!config.excludeFromSemantics) {
       RenderSemanticsGestureHandler semanticsGestureHandler = context.findRenderObject();
       context.visitChildElements((RenderObjectElement element) {
-        element.widget.updateRenderObject(semanticsGestureHandler, null);
+        element.widget.updateRenderObject(context, semanticsGestureHandler);
       });
     }
   }
@@ -458,13 +458,13 @@ class _GestureSemantics extends OneChildRenderObjectWidget {
     assert(false);
   }
 
-  RenderSemanticsGestureHandler createRenderObject() {
+  RenderSemanticsGestureHandler createRenderObject(BuildContext context) {
     RenderSemanticsGestureHandler result = new RenderSemanticsGestureHandler();
-    updateRenderObject(result, null);
+    updateRenderObject(context, result);
     return result;
   }
 
-  void updateRenderObject(RenderSemanticsGestureHandler renderObject, _GestureSemantics oldWidget) {
+  void updateRenderObject(BuildContext context, RenderSemanticsGestureHandler renderObject) {
     Map<Type, GestureRecognizer> recognizers = owner._recognizers;
     renderObject
       ..onTap = recognizers.containsKey(TapGestureRecognizer) ? _handleTap : null

packages/flutter/lib/src/widgets/mixed_viewport.dart

@@ -37,7 +37,7 @@ class MixedViewport extends RenderObjectWidget {
 
   // we don't pass constructor arguments to the RenderBlockViewport() because until
   // we know our children, the constructor arguments we could give have no effect
-  RenderBlockViewport createRenderObject() => new RenderBlockViewport();
+  RenderBlockViewport createRenderObject(BuildContext context) => new RenderBlockViewport();
 
   _ChangeDescription evaluateChangesFrom(MixedViewport oldWidget) {
     if (direction != oldWidget.direction ||

packages/flutter/lib/src/widgets/pageable_list.dart

@@ -242,7 +242,7 @@ class PageViewport extends VirtualViewportFromIterable {
   final Painter overlayPainter;
   final Iterable<Widget> children;
 
-  RenderList createRenderObject() => new RenderList();
+  RenderList createRenderObject(BuildContext context) => new RenderList();
 
   _PageViewportElement createElement() => new _PageViewportElement(this);
 }

packages/flutter/lib/src/widgets/performance_overlay.dart

@@ -56,12 +56,12 @@ class PerformanceOverlay extends LeafRenderObjectWidget {
   /// how many frame intervals).
   final int rasterizerThreshold;
 
-  RenderPerformanceOverlay createRenderObject() => new RenderPerformanceOverlay(
+  RenderPerformanceOverlay createRenderObject(BuildContext context) => new RenderPerformanceOverlay(
     optionsMask: optionsMask,
     rasterizerThreshold: rasterizerThreshold
   );
 
-  void updateRenderObject(RenderPerformanceOverlay renderObject, RenderObjectWidget oldWidget) {
+  void updateRenderObject(BuildContext context, RenderPerformanceOverlay renderObject) {
     renderObject
       ..optionsMask = optionsMask
       ..rasterizerThreshold = rasterizerThreshold;

packages/flutter/lib/src/widgets/scrollable_grid.dart

@@ -80,7 +80,7 @@ class GridViewport extends VirtualViewportFromIterable {
   // TODO(abarth): Support horizontal scrolling;
   Axis get scrollDirection => Axis.vertical;
 
-  RenderGrid createRenderObject() => new RenderGrid(delegate: delegate);
+  RenderGrid createRenderObject(BuildContext context) => new RenderGrid(delegate: delegate);
 
   _GridViewportElement createElement() => new _GridViewportElement(this);
 }

packages/flutter/lib/src/widgets/scrollable_list.dart

@@ -140,7 +140,7 @@ class _VirtualListViewport extends VirtualViewport {
     return scrollOffset - _leadingPadding;
   }
 
-  RenderList createRenderObject() => new RenderList(itemExtent: itemExtent);
+  RenderList createRenderObject(BuildContext context) => new RenderList(itemExtent: itemExtent);
 
   _VirtualListViewportElement createElement() => new _VirtualListViewportElement(this);
 }

packages/flutter_sprites/lib/src/sprite_widget.dart

@@ -24,9 +24,9 @@ class SpriteWidget extends OneChildRenderObjectWidget {
   ///     var mySpriteWidget = new SpriteWidget(mySpriteTree, SpriteBoxTransformMode.fixedHeight);
   SpriteWidget(this.rootNode, [this.transformMode = SpriteBoxTransformMode.letterbox]);
 
-  SpriteBox createRenderObject() => new SpriteBox(rootNode, transformMode);
+  SpriteBox createRenderObject(BuildContext context) => new SpriteBox(rootNode, transformMode);
 
-  void updateRenderObject(SpriteBox renderObject, SpriteWidget oldWidget) {
+  void updateRenderObject(BuildContext context, SpriteBox renderObject) {
     renderObject
       ..rootNode = rootNode
       ..transformMode = transformMode;

packages/playfair/lib/src/base.dart

@@ -57,9 +57,9 @@ class _ChartWrapper extends LeafRenderObjectWidget {
   final TextTheme textTheme;
   final ChartData data;
 
-  _RenderChart createRenderObject() => new _RenderChart(textTheme: textTheme, data: data);
+  _RenderChart createRenderObject(BuildContext context) => new _RenderChart(textTheme: textTheme, data: data);
 
-  void updateRenderObject(_RenderChart renderObject, _ChartWrapper oldWidget) {
+  void updateRenderObject(BuildContext context, _RenderChart renderObject) {
     renderObject
       ..textTheme = textTheme
       ..data = data;