Make it possible to custom-paint without an Element.

sky/engine/core/dom/Document.cpp

Index: sky/engine/core/dom/Document.cpp
diff --git a/sky/engine/core/dom/Document.cpp b/sky/engine/core/dom/Document.cpp
index 38bb75179d003ba9db25ba590e98f101d7748d2d..2b37f28f7ecafc4db297bfb9f6979456130dc959 100644
--- a/sky/engine/core/dom/Document.cpp
+++ b/sky/engine/core/dom/Document.cpp
@@ -104,6 +104,8 @@
 #include "sky/engine/core/page/EventHandler.h"
 #include "sky/engine/core/page/FocusController.h"
 #include "sky/engine/core/page/Page.h"
+#include "sky/engine/core/painting/PaintingTasks.h"
+#include "sky/engine/core/painting/Picture.h"
 #include "sky/engine/core/rendering/HitTestResult.h"
 #include "sky/engine/core/rendering/RenderView.h"
 #include "sky/engine/platform/DateComponents.h"
@@ -2204,6 +2206,19 @@ bool Document::hasFocus() const
     return focusedFrame && focusedFrame == frame();
 }
 
+Picture* Document::rootPicture() const
+{
+    return m_picture.get();
+}
+
+void Document::setRootPicture(PassRefPtr<Picture> picture)
+{
+    m_picture = picture;
+    if (m_picture)
+        PaintingTasks::enqueueCommit(this, m_picture->displayList());
+    scheduleVisualUpdate();
+}
+
 } // namespace blink
 
 #ifndef NDEBUG