Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/html/canvas/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 97 matching lines @@
     if (size_t stackSize = m_stateStack.size()) {
         if (GraphicsContext* context = canvas()->existingDrawingContext()) {
             while (--stackSize)
                 context->restore();
         }
     }
 }
 
 CanvasRenderingContext2D::~CanvasRenderingContext2D()
 {
+#if !ENABLE(OILPAN)
 #if !ASSERT_DISABLED
     unwindStateStack();
 #endif
+#endif
 }
 
 bool CanvasRenderingContext2D::isAccelerated() const
 {
     if (!canvas()->hasImageBuffer())
         return false;
     GraphicsContext* context = drawingContext();
     return context && context->isAccelerated();
 }
 
@@ skipping 22 matching lines @@
         if (contextLostRestoredEventsEnabled()) {
             m_dispatchContextRestoredEventTimer.startOneShot(0, FROM_HERE);
         } else {
             // legacy synchronous context restoration.
             reset();
             m_isContextLost = false;
         }
     }
 }
 
+void CanvasRenderingContext2D::trace(Visitor* visitor)
+{
+#if ENABLE(OILPAN)
+    visitor->trace(m_stateStack);
+#endif
+    visitor->trace(m_fetchedFonts);
+    CanvasRenderingContext::trace(visitor);
+}
+
 void CanvasRenderingContext2D::dispatchContextLostEvent(Timer<CanvasRenderingContext2D>*)
 {
     if (contextLostRestoredEventsEnabled()) {
         RefPtrWillBeRawPtr<Event> event = Event::createCancelable(EventTypeNames::contextlost);
         canvas()->dispatchEvent(event);
         if (event->defaultPrevented()) {
             m_contextRestorable = false;
         }
     }
 
@@ skipping 2261 matching lines @@
     c->setAlphaAsFloat(1.0);
     c->clearShadow();
     c->setCompositeOperation(CompositeSourceOver, blink::WebBlendModeNormal);
     c->drawFocusRing(path, focusRingWidth, focusRingOutline, focusRingColor);
     c->restore();
 
     didDraw(dirtyRect);
 }
 
 } // namespace WebCore