Make it possible to custom-paint without an Element.

sky/engine/core/painting/Canvas.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/PaintingContext.h"
+#include "sky/engine/core/painting/PictureRecorder.h"
 
 #include "sky/engine/core/dom/Document.h"
 #include "sky/engine/core/dom/Element.h"
 #include "sky/engine/core/painting/PaintingTasks.h"
 #include "sky/engine/platform/geometry/IntRect.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace blink {
 
-PassRefPtr<PaintingContext> PaintingContext::create(PassRefPtr<Element> element, const FloatSize& size)
-{
-    return adoptRef(new PaintingContext(element, size));
-}
-
-PaintingContext::PaintingContext(PassRefPtr<Element> element, const FloatSize& size)
-    : m_element(element)
-    , m_size(size)
+Canvas::Canvas(const FloatSize& size)
+    : m_size(size)
 {
     m_displayList = adoptRef(new DisplayList);
     m_canvas = m_displayList->beginRecording(expandedIntSize(m_size));
 }
 
-PaintingContext::~PaintingContext()
+Canvas::~Canvas()
 {
 }
 
-void PaintingContext::drawCircle(double x, double y, double radius, Paint* paint)
+void Canvas::drawCircle(double x, double y, double radius, Paint* paint)
 {
     if (!m_canvas)
         return;
     ASSERT(paint);
     ASSERT(m_displayList->isRecording());
     m_canvas->drawCircle(x, y, radius, paint->paint());
 }
 
-void PaintingContext::commit()
+PassRefPtr<DisplayList> Canvas::finishRecording()
 {
-    if (!m_canvas)
-        return;
+    if (!isRecording())
+        return nullptr;
+    m_canvas = nullptr;
     m_displayList->endRecording();
-    m_canvas = nullptr;
-    PaintingTasks::enqueueCommit(m_element, m_displayList.release());
-    m_element->document().scheduleVisualUpdate();
+    return m_displayList.release();
 }
 
 } // namespace blink