Add a basic custom painting facility to Sky

This CL adds just enough custom painting to Sky to make
sky/examples/painting/circle.sky draw a circle. Over time, we should be able to
elaborate this system into something interesting and to make it actually work
in a reasonable way.

R=ojan@chromium.org

Review URL: https://codereview.chromium.org/1017593005

engine/bindings/scripts/dart_callback_interface.py

@@ -124,7 +124,12 @@ def generate_arguments_contents(arguments, call_with_this_handle):
             for argument in arguments]
     if call_with_this_handle:
         argument_declarations.insert(0, 'ScriptValue thisValue')
+
+    dart_argument_declarations = [
+            '%s %s' % (dart_types.idl_type_to_dart_type(argument.idl_type), argument.name)
+            for argument in arguments]
     return  {
         'argument_declarations': argument_declarations,
+        'dart_argument_declarations': dart_argument_declarations,
         'arguments': [generate_argument(argument) for argument in arguments],
     }

engine/bindings/scripts/dart_types.py

@@ -718,7 +718,7 @@ CPP_VALUE_TO_DART_VALUE = {
     'DartValue': 'DartConverter<DartValue*>::ToDart({cpp_value})',
     # General
     'array': 'VectorToDart({cpp_value})',
-    'DOMWrapper': 'Dart{idl_type}::toDart({cpp_value})',
+    'DOMWrapper': 'DartConverter<{idl_type}*>::ToDart({cpp_value})',
 }
 
 

engine/bindings/scripts/templates/callback_interface_dart.template

@@ -5,4 +5,4 @@
 // WARNING: Do not edit - generated code.
 part of dart.sky;
 
-typedef void {{cpp_class}}({{methods[0].argument_declarations | join(', ')}});
+typedef void {{cpp_class}}({{methods[0].dart_argument_declarations | join(', ')}});
\ No newline at end of file

engine/core/core.gni

@@ -942,6 +942,8 @@ sky_core_files = [
   "page/SpellCheckerClient.h",
   "painting/Paint.cpp",
   "painting/Paint.h",
+  "painting/PaintingCallback.cpp",
+  "painting/PaintingCallback.h",
   "painting/PaintingContext.cpp",
   "painting/PaintingContext.h",
   "rendering/BidiRun.h",
@@ -1239,6 +1241,7 @@ core_idl_files = get_path_info([
                                  "html/TextMetrics.idl",
                                  "html/VoidCallback.idl",
                                  "painting/Paint.idl",
+                                 "painting/PaintingCallback.idl",
                                  "painting/PaintingContext.idl",
                                ],
                                "abspath")

engine/core/dom/Element.cpp

@@ -26,6 +26,7 @@
 #include "sky/engine/config.h"
 #include "sky/engine/core/dom/Element.h"
 
+#include "base/bind.h"
 #include "gen/sky/core/CSSValueKeywords.h"
 #include "gen/sky/core/HTMLNames.h"
 #include "gen/sky/platform/RuntimeEnabledFeatures.h"
@@ -49,6 +50,7 @@
 #include "sky/engine/core/dom/ElementRareData.h"
 #include "sky/engine/core/dom/ElementTraversal.h"
 #include "sky/engine/core/dom/ExceptionCode.h"
+#include "sky/engine/core/dom/Microtask.h"
 #include "sky/engine/core/dom/MutationObserverInterestGroup.h"
 #include "sky/engine/core/dom/MutationRecord.h"
 #include "sky/engine/core/dom/NodeRenderStyle.h"
@@ -75,6 +77,8 @@
 #include "sky/engine/core/page/ChromeClient.h"
 #include "sky/engine/core/page/FocusController.h"
 #include "sky/engine/core/page/Page.h"
+#include "sky/engine/core/painting/PaintingContext.h"
+#include "sky/engine/core/painting/PaintingCallback.h"
 #include "sky/engine/core/rendering/RenderLayer.h"
 #include "sky/engine/core/rendering/RenderView.h"
 #include "sky/engine/platform/EventDispatchForbiddenScope.h"
@@ -413,6 +417,38 @@ PassRefPtr<ClientRect> Element::getBoundingClientRect()
     return ClientRect::create(result);
 }
 
+// TODO(abarth): We should schedule this work at a more reasonable time.
+static void handlePaintingCommit(RefPtr<Element> element, RefPtr<PaintingContext> context)
+{
+    if (!element->document().isActive())
+        return;
+    element->document().updateLayout();
+    RenderObject* renderer = element->renderer();
+    if (!renderer || !renderer->isBox())
+        return;
+    toRenderBox(renderer)->setCustomPainting(context->takeDisplayList());
+    element->document().scheduleVisualUpdate();
+}
+
+// TODO(abarth): We should schedule this work at a more reasonable time.
+static void runPaintingCallback(RefPtr<Element> element, PassOwnPtr<PaintingCallback> callback)
+{
+    if (!element->document().isActive())
+        return;
+    element->document().updateLayout();
+    RenderObject* renderer = element->renderer();
+    if (!renderer || !renderer->isBox())
+        return;
+    RefPtr<PaintingContext> context = PaintingContext::create(
+        toRenderBox(renderer)->size(), base::Bind(&handlePaintingCommit, element));
+    callback->handleEvent(context.get());
+}
+
+void Element::requestPaint(PassOwnPtr<PaintingCallback> callback)
+{
+    Microtask::enqueueMicrotask(base::Bind(&runPaintingCallback, this, callback));
+}
+
 void Element::setAttribute(const AtomicString& localName, const AtomicString& value, ExceptionState& exceptionState)
 {
     if (!Document::isValidName(localName)) {

engine/core/dom/Element.h

@@ -51,6 +51,7 @@ class ExceptionState;
 class Image;
 class IntSize;
 class MutableStylePropertySet;
+class PaintingCallback;
 class PropertySetCSSStyleDeclaration;
 class PseudoElement;
 class ShadowRoot;
@@ -126,6 +127,8 @@ public:
     PassRefPtr<ClientRectList> getClientRects();
     PassRefPtr<ClientRect> getBoundingClientRect();
 
+    void requestPaint(PassOwnPtr<PaintingCallback>);
+
     virtual void didMoveToNewDocument(Document&) override;
 
     CSSStyleDeclaration* style();

engine/core/dom/Element.idl

@@ -16,6 +16,8 @@
 
   readonly attribute ShadowRoot shadowRoot;
 
+  void requestPaint(PaintingCallback callback);
+
   // TODO(abarth): Move to Node.
   readonly attribute CSSStyleDeclaration style;
 

engine/core/painting/Paint.h

@@ -29,7 +29,7 @@ public:
 
     void setARGB(unsigned a, unsigned r, unsigned g, unsigned b)
     {
-        m_paint.setARGB(r, g, b, a);
+        m_paint.setARGB(a, r, g, b);
     }
 
     const SkPaint& paint() const { return m_paint; }

engine/core/painting/PaintingCallback.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sky/engine/config.h"
+#include "sky/engine/core/painting/PaintingCallback.h"
+
+namespace blink {
+
+PaintingCallback::~PaintingCallback()
+{
+}
+
+} // namespace blink

engine/core/painting/PaintingCallback.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SKY_ENGINE_CORE_PAINTING_PAINTINGCALLBACK_H_
+#define SKY_ENGINE_CORE_PAINTING_PAINTINGCALLBACK_H_
+
+namespace blink {
+class PaintingContext;
+
+class PaintingCallback {
+public:
+    virtual ~PaintingCallback();
+    virtual void handleEvent(PaintingContext* context) = 0;
+};
+
+} // namespace blink
+
+#endif  // SKY_ENGINE_CORE_PAINTING_PAINTINGCALLBACK_H_

engine/core/painting/PaintingCallback.idl

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+callback interface PaintingCallback {
+    void handleEvent(PaintingContext context);
+};

engine/core/painting/PaintingContext.cpp

@@ -5,15 +5,19 @@
 #include "sky/engine/config.h"
 #include "sky/engine/core/painting/PaintingContext.h"
 
+#include "base/bind.h"
+#include "sky/engine/core/dom/Microtask.h"
 #include "sky/engine/platform/geometry/IntRect.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace blink {
 
-PaintingContext::PaintingContext(const FloatRect& bounds)
+PaintingContext::PaintingContext(const FloatSize& size, const CommitCallback& commitCallback)
+    : m_size(size)
+    , m_commitCallback(commitCallback)
 {
-    m_displayList = adoptRef(new DisplayList(bounds));
-    m_canvas = m_displayList->beginRecording(enclosingIntRect(bounds).size());
+    m_displayList = adoptRef(new DisplayList);
+    m_canvas = m_displayList->beginRecording(expandedIntSize(size));
 }
 
 PaintingContext::~PaintingContext()
@@ -31,8 +35,11 @@ void PaintingContext::drawCircle(double x, double y, double radius, Paint* paint
 
 void PaintingContext::commit()
 {
+    if (!m_canvas)
+        return;
     m_displayList->endRecording();
     m_canvas = nullptr;
+    Microtask::enqueueMicrotask(base::Bind(m_commitCallback, this));
 }
 
 } // namespace blink

engine/core/painting/PaintingContext.h

@@ -5,6 +5,7 @@
 #ifndef SKY_ENGINE_CORE_PAINTING_PAINTINGCONTEXT_H_
 #define SKY_ENGINE_CORE_PAINTING_PAINTINGCONTEXT_H_
 
+#include "base/callback.h"
 #include "sky/engine/core/painting/Paint.h"
 #include "sky/engine/platform/graphics/DisplayList.h"
 #include "sky/engine/tonic/dart_wrappable.h"
@@ -16,18 +17,31 @@ namespace blink {
 class PaintingContext : public RefCounted<PaintingContext>, public DartWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
+    typedef base::Callback<void (RefPtr<PaintingContext>)> CommitCallback;
+
     ~PaintingContext() override;
-    PassRefPtr<PaintingContext> create(const FloatRect& bounds) { return adoptRef(new PaintingContext(bounds)); }
+    static PassRefPtr<PaintingContext> create(const FloatSize& size, const CommitCallback& commitCallback)
+    {
+        return adoptRef(new PaintingContext(size, commitCallback));
+    }
 
-    double height() const { return m_displayList->bounds().height(); }
-    double width() const { return m_displayList->bounds().width(); }
+    double height() const { return m_size.height(); }
+    double width() const { return m_size.width(); }
 
     void drawCircle(double x, double y, double radius, Paint* paint);
     void commit();
 
+    PassRefPtr<DisplayList> takeDisplayList()
+    {
+        ASSERT(!m_canvas);
+        return m_displayList.release();
+    }
+
 private:
-    PaintingContext(const FloatRect& bounds);
+    PaintingContext(const FloatSize& size, const CommitCallback& commitCallback);
 
+    FloatSize m_size;
+    CommitCallback m_commitCallback;
     RefPtr<DisplayList> m_displayList;
     SkCanvas* m_canvas;
 };

engine/core/painting/PaintingContext.idl

@@ -7,6 +7,5 @@ interface PaintingContext {
   readonly attribute double width;
 
   void drawCircle(double x, double y, double radius, Paint paint);
-
   void commit();
 };

engine/core/rendering/RenderBox.cpp

@@ -989,6 +989,12 @@ void RenderBox::paintBoxDecorationBackground(PaintInfo& paintInfo, const LayoutP
     LayoutRect paintRect = borderBoxRect();
     paintRect.moveBy(paintOffset);
     paintBoxDecorationBackgroundWithRect(paintInfo, paintOffset, paintRect);
+    // TODO(abarth): Currently we only draw m_customPainting if we happen to
+    // have a box decoration or a background. Instead, we should probably have
+    // another function like paintBoxDecorationBackground that subclasses can
+    // call to draw m_customPainting.
+    if (m_customPainting)
+        paintInfo.context->drawDisplayList(m_customPainting.get(), paintRect.location());
 }
 
 void RenderBox::paintBoxDecorationBackgroundWithRect(PaintInfo& paintInfo, const LayoutPoint& paintOffset, const LayoutRect& paintRect)

engine/core/rendering/RenderBox.h

@@ -450,6 +450,8 @@ public:
 
     bool hasSameDirectionAs(const RenderBox* object) const { return style()->direction() == object->style()->direction(); }
 
+    void setCustomPainting(PassRefPtr<DisplayList> customPainting) { m_customPainting = customPainting; }
+
 protected:
     virtual void willBeDestroyed() override;
 
@@ -569,6 +571,7 @@ protected:
     OwnPtr<TransformationMatrix> m_transform;
 
 private:
+    RefPtr<DisplayList> m_customPainting;
     OwnPtr<RenderLayer> m_layer;
     OwnPtr<RenderBoxRareData> m_rareData;
 };

engine/platform/graphics/DisplayList.cpp

@@ -38,8 +38,7 @@
 
 namespace blink {
 
-DisplayList::DisplayList(const FloatRect& bounds)
-    : m_bounds(bounds)
+DisplayList::DisplayList()
 {
 }
 
@@ -47,11 +46,6 @@ DisplayList::~DisplayList()
 {
 }
 
-const FloatRect& DisplayList::bounds() const
-{
-    return m_bounds;
-}
-
 SkPicture* DisplayList::picture() const
 {
     return m_picture.get();

engine/platform/graphics/DisplayList.h

@@ -49,11 +49,9 @@ class PLATFORM_EXPORT DisplayList final : public WTF::RefCounted<DisplayList> {
     WTF_MAKE_FAST_ALLOCATED;
     WTF_MAKE_NONCOPYABLE(DisplayList);
 public:
-    DisplayList(const FloatRect&);
+    DisplayList();
     ~DisplayList();
 
-    const FloatRect& bounds() const;
-
     // This entry point will return 0 when the DisplayList is in the
     // midst of recording (i.e., between a beginRecording/endRecording pair)
     // and if no recording has ever been completed. Otherwise it will return
@@ -65,7 +63,6 @@ public:
     void endRecording();
 
 private:
-    FloatRect m_bounds;
     RefPtr<SkPicture> m_picture;
     OwnPtr<SkPictureRecorder> m_recorder;
 };

engine/platform/graphics/GraphicsContext.cpp

@@ -98,19 +98,6 @@ struct GraphicsContext::CanvasSaveState {
     int m_restoreCount;
 };
 
-struct GraphicsContext::RecordingState {
-    RecordingState(SkCanvas* currentCanvas, const SkMatrix& currentMatrix, PassRefPtr<DisplayList> displayList)
-        : m_savedCanvas(currentCanvas)
-        , m_displayList(displayList)
-        , m_savedMatrix(currentMatrix)
-    {
-    }
-
-    SkCanvas* m_savedCanvas;
-    RefPtr<DisplayList> m_displayList;
-    const SkMatrix m_savedMatrix;
-};
-
 GraphicsContext::GraphicsContext(SkCanvas* canvas, DisabledMode disableContextOrPainting)
     : m_canvas(canvas)
     , m_paintStateStack()
@@ -144,7 +131,6 @@ GraphicsContext::~GraphicsContext()
         ASSERT(!m_paintStateIndex);
         ASSERT(!m_paintState->saveCount());
         ASSERT(!m_layerCount);
-        ASSERT(m_recordingStateStack.isEmpty());
         ASSERT(m_canvasStateStack.isEmpty());
     }
 #endif
@@ -332,14 +318,7 @@ SkMatrix GraphicsContext::getTotalMatrix() const
     if (contextDisabled())
         return SkMatrix::I();
 
-    if (!isRecording())
-        return m_canvas->getTotalMatrix();
-
-    const RecordingState& recordingState = m_recordingStateStack.last();
-    SkMatrix totalMatrix = recordingState.m_savedMatrix;
-    totalMatrix.preConcat(m_canvas->getTotalMatrix());
-
-    return totalMatrix;
+    return m_canvas->getTotalMatrix();
 }
 
 void GraphicsContext::adjustTextRenderMode(SkPaint* paint)
@@ -447,64 +426,18 @@ void GraphicsContext::endLayer()
 #endif
 }
 
-void GraphicsContext::beginRecording(const FloatRect& bounds)
-{
-    RefPtr<DisplayList> displayList = adoptRef(new DisplayList(bounds));
-
-    SkCanvas* savedCanvas = m_canvas;
-    SkMatrix savedMatrix = getTotalMatrix();
-
-    if (!contextDisabled()) {
-        IntRect recordingRect = enclosingIntRect(bounds);
-        m_canvas = displayList->beginRecording(recordingRect.size());
-
-        // We want the bounds offset mapped to (0, 0), such that the display list content
-        // is fully contained within the SkPictureRecord's bounds.
-        if (!toFloatSize(bounds.location()).isZero()) {
-            m_canvas->translate(-bounds.x(), -bounds.y());
-            // To avoid applying the offset repeatedly in getTotalMatrix(), we pre-apply it here.
-            savedMatrix.preTranslate(bounds.x(), bounds.y());
-        }
-    }
-
-    m_recordingStateStack.append(RecordingState(savedCanvas, savedMatrix, displayList));
-}
-
-PassRefPtr<DisplayList> GraphicsContext::endRecording()
-{
-    ASSERT(!m_recordingStateStack.isEmpty());
-
-    RecordingState recording = m_recordingStateStack.last();
-    if (!contextDisabled()) {
-        ASSERT(recording.m_displayList->isRecording());
-        recording.m_displayList->endRecording();
-    }
-
-    m_recordingStateStack.removeLast();
-    m_canvas = recording.m_savedCanvas;
-
-    return recording.m_displayList.release();
-}
-
-bool GraphicsContext::isRecording() const
-{
-    return !m_recordingStateStack.isEmpty();
-}
-
-void GraphicsContext::drawDisplayList(DisplayList* displayList)
+void GraphicsContext::drawDisplayList(DisplayList* displayList, const FloatPoint& point)
 {
     ASSERT(displayList);
-    ASSERT(!displayList->isRecording());
 
-    if (contextDisabled() || displayList->bounds().isEmpty())
+    if (contextDisabled())
         return;
 
     realizeCanvasSave();
 
-    const FloatRect& bounds = displayList->bounds();
-    if (bounds.x() || bounds.y()) {
+    if (point.x() || point.y()) {
         SkMatrix m;
-        m.setTranslate(bounds.x(), bounds.y());
+        m.setTranslate(point.x(), point.y());
         m_canvas->drawPicture(displayList->picture(), &m, 0);
     } else {
         m_canvas->drawPicture(displayList->picture());

engine/platform/graphics/GraphicsContext.h

@@ -155,7 +155,7 @@ public:
     // rotations of thin ("hairline") images.
     // Note: This will only be reliable when the device pixel scale/ratio is
     // fixed (e.g. when drawing to context backed by an ImageBuffer).
-    void disableAntialiasingOptimizationForHairlineImages() { ASSERT(!isRecording()); m_antialiasHairlineImages = true; }
+    void disableAntialiasingOptimizationForHairlineImages() { m_antialiasHairlineImages = true; }
     bool shouldAntialiasHairlineImages() const { return m_antialiasHairlineImages; }
 
     void setShouldClampToSourceRect(bool clampToSourceRect) { mutableState()->setShouldClampToSourceRect(clampToSourceRect); }
@@ -258,7 +258,7 @@ public:
         const IntRect&, const IntSize& innerTopLeft, const IntSize& innerTopRight, const IntSize& innerBottomLeft, const IntSize& innerBottomRight, const Color&);
     void fillBetweenRoundedRects(const RoundedRect&, const RoundedRect&, const Color&);
 
-    void drawDisplayList(DisplayList*);
+    void drawDisplayList(DisplayList*, const FloatPoint&);
 
     void drawImage(Image*, const IntPoint&, CompositeOperator = CompositeSourceOver, RespectImageOrientationEnum = DoNotRespectImageOrientation);
     void drawImage(Image*, const IntRect&, CompositeOperator = CompositeSourceOver, RespectImageOrientationEnum = DoNotRespectImageOrientation);
@@ -319,11 +319,6 @@ public:
     void beginLayer(float opacity, CompositeOperator, const FloatRect* = 0, ColorFilter = ColorFilterNone, ImageFilter* = 0);
     void endLayer();
 
-    // Instead of being dispatched to the active canvas, draw commands following beginRecording()
-    // are stored in a display list that can be replayed at a later time.
-    void beginRecording(const FloatRect& bounds);
-    PassRefPtr<DisplayList> endRecording();
-
     bool hasShadow() const;
     void setShadow(const FloatSize& offset, float blur, const Color&,
         DrawLooperBuilder::ShadowTransformMode = DrawLooperBuilder::ShadowRespectsTransforms,
@@ -466,8 +461,6 @@ private:
 
     void fillRectWithRoundedHole(const IntRect&, const RoundedRect& roundedHoleRect, const Color&);
 
-    bool isRecording() const;
-
     // null indicates painting is contextDisabled. Never delete this object.
     SkCanvas* m_canvas;
 
@@ -487,9 +480,6 @@ private:
     Vector<CanvasSaveState> m_canvasStateStack;
     bool m_pendingCanvasSave;
 
-    struct RecordingState;
-    Vector<RecordingState> m_recordingStateStack;
-
 #if ENABLE(ASSERT)
     unsigned m_layerCount;
     bool m_disableDestructionChecks;

engine/platform/graphics/GraphicsContextTest.cpp

@@ -1117,82 +1117,4 @@ TEST(GraphicsContextTest, OpaqueRegionForLayerWithRectDeviceClip)
     EXPECT_PIXELS_MATCH(bitmap, context.opaqueRegion().asRect());
 }
 
-#define DISPATCH1(c1, c2, op, param1) do { c1.op(param1); c2.op(param1); } while (0);
-#define DISPATCH2(c1, c2, op, param1, param2) do { c1.op(param1, param2); c2.op(param1, param2); } while (0);
-
-TEST(GraphicsContextTest, RecordingTotalMatrix)
-{
-    SkBitmap bitmap;
-    bitmap.allocN32Pixels(400, 400);
-    bitmap.eraseColor(0);
-    SkCanvas canvas(bitmap);
-    GraphicsContext context(&canvas);
-
-    SkCanvas controlCanvas(400, 400);
-    GraphicsContext controlContext(&controlCanvas);
-
-    EXPECT_EQ(context.getCTM(), controlContext.getCTM());
-    DISPATCH2(context, controlContext, scale, 2, 2);
-    EXPECT_EQ(context.getCTM(), controlContext.getCTM());
-
-    controlContext.save();
-    context.beginRecording(FloatRect(0, 0, 200, 200));
-    DISPATCH2(context, controlContext, translate, 10, 10);
-    EXPECT_EQ(context.getCTM(), controlContext.getCTM());
-
-    controlContext.save();
-    context.beginRecording(FloatRect(10, 10, 100, 100));
-    DISPATCH1(context, controlContext, rotate, 45);
-    EXPECT_EQ(context.getCTM(), controlContext.getCTM());
-
-    controlContext.restore();
-    context.endRecording();
-    EXPECT_EQ(context.getCTM(), controlContext.getCTM());
-
-    controlContext.restore();
-    context.endRecording();
-    EXPECT_EQ(context.getCTM(), controlContext.getCTM());
-}
-
-TEST(GraphicsContextTest, DisplayList)
-{
-    FloatRect rect(0, 0, 1, 1);
-    RefPtr<DisplayList> dl = adoptRef(new DisplayList(rect));
-
-    // picture() returns 0 initially
-    SkPicture* pic = dl->picture();
-    EXPECT_FALSE(pic);
-
-    // endRecording without a beginRecording does nothing
-    dl->endRecording();
-    pic = dl->picture();
-    EXPECT_FALSE(pic);
-
-    // Two beginRecordings in a row generate two canvases.
-    // Unfortunately the new one could be allocated in the same
-    // spot as the old one so ref the first one to prolong its life.
-    IntSize size(1, 1);
-    SkCanvas* canvas1 = dl->beginRecording(size);
-    EXPECT_TRUE(canvas1);
-    canvas1->ref();
-    SkCanvas* canvas2 = dl->beginRecording(size);
-    EXPECT_TRUE(canvas2);
-
-    EXPECT_NE(canvas1, canvas2);
-    EXPECT_TRUE(canvas1->unique());
-    canvas1->unref();
-
-    EXPECT_TRUE(dl->isRecording());
-
-    // picture() returns 0 during recording
-    pic = dl->picture();
-    EXPECT_FALSE(pic);
-
-    // endRecording finally makes the picture accessible
-    dl->endRecording();
-    pic = dl->picture();
-    EXPECT_TRUE(pic);
-    EXPECT_TRUE(pic->unique());
-}
-
 } // namespace

engine/platform/graphics/filters/SourceGraphic.cpp

@@ -63,17 +63,9 @@ void SourceGraphic::applySoftware()
     }
 }
 
-void SourceGraphic::setDisplayList(PassRefPtr<DisplayList> displayList)
-{
-    m_displayList = displayList;
-}
-
 PassRefPtr<SkImageFilter> SourceGraphic::createImageFilter(SkiaImageFilterBuilder*)
 {
-    if (!m_displayList)
-        return nullptr;
-
-    return adoptRef(SkPictureImageFilter::Create(m_displayList->picture(), m_displayList->bounds()));
+    return nullptr;
 }
 
 TextStream& SourceGraphic::externalRepresentation(TextStream& ts, int indent) const

engine/platform/graphics/filters/SourceGraphic.h

@@ -41,9 +41,6 @@ public:
     virtual TextStream& externalRepresentation(TextStream&, int indention) const override;
     PassRefPtr<SkImageFilter> createImageFilter(SkiaImageFilterBuilder*) override;
 
-    void setDisplayList(PassRefPtr<DisplayList>);
-
-
 private:
     SourceGraphic(Filter* filter)
         : FilterEffect(filter)
@@ -52,7 +49,7 @@ private:
     }
 
     virtual void applySoftware() override;
-    RefPtr<DisplayList> m_displayList;
+    // TODO(sky): This class appears to be broken...
 };
 
 } //namespace blink

examples/painting/circle.sky

+<sky>
+<style>
+div {
+    height: 200px;
+    background-color: lightblue;
+}
+</style>
+<div id="canvas" />
+<script>
+import 'dart:math' as math;
+import 'dart:sky';
+
+void main() {
+  var element = document.getElementById('canvas');
+  element.requestPaint((PaintingContext context) {
+    Paint paint = new Paint();
+    paint.setARGB(128, 0, 255, 0);
+    double radius = math.min(context.width, context.height) / 2.0;
+    context.drawCircle(context.width / 2.0, context.height / 2.0, radius, paint);
+    context.commit();
+  });
+}
+</script>
+</sky>