Fix Slimming Paint WebGL printing

Source/platform/graphics/paint/DisplayItemListContextRecorder.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 DisplayItemListContextRecorder_h
 #define DisplayItemListContextRecorder_h
 
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 #include "wtf/OwnPtr.h"
 
 namespace blink {
 
 class DisplayItemListContextRecorder {
     WTF_MAKE_NONCOPYABLE(DisplayItemListContextRecorder);
     STACK_ALLOCATED();
 public:
     DisplayItemListContextRecorder(GraphicsContext& context)
         : m_initialContext(context)
     {
         if (!RuntimeEnabledFeatures::slimmingPaintEnabled())
             return;
 
         m_displayItemList = DisplayItemList::create();
         m_displayItemListContext = adoptPtr(new GraphicsContext(m_displayItemList.get(),
             context.contextDisabled() ? GraphicsContext::FullyDisabled : GraphicsContext::NothingDisabled));
+        m_displayItemListContext->setDeviceScaleFactor(context.deviceScaleFactor());
+        m_displayItemListContext->setPrinting(context.printing());
     }
 
     ~DisplayItemListContextRecorder()
     {
         if (!RuntimeEnabledFeatures::slimmingPaintEnabled())
             return;
 
         ASSERT(m_displayItemList);
         m_displayItemList->commitNewDisplayItemsAndReplay(m_initialContext);
     }
 
     GraphicsContext& context() const { return m_displayItemList ? *m_displayItemListContext : m_initialContext; }
 
 private:
     GraphicsContext& m_initialContext;
     OwnPtr<DisplayItemList> m_displayItemList;
     OwnPtr<GraphicsContext> m_displayItemListContext;
 };
 
 } // namespace blink
 
 #endif // DisplayItemListContextRecorder_h