Use refs for GraphicsContext

third_party/WebKit/Source/core/paint/SVGPaintContext.h

 /**
  * Copyright (C) 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Google, Inc.  All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2012 Zoltan Herczeg <zherczeg@webkit.org>.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 27 matching lines @@
 
 class LayoutObject;
 class LayoutSVGResourceFilter;
 class LayoutSVGResourceMasker;
 class SVGResources;
 
 class SVGPaintContext {
     STACK_ALLOCATED();
 public:
     SVGPaintContext(const LayoutObject& object, const PaintInfo& paintInfo)
-        : m_object(&object)
+        : m_object(object)
         , m_paintInfo(paintInfo)
-        , m_originalPaintInfo(&paintInfo)
         , m_filter(nullptr)
         , m_clipper(nullptr)
         , m_clipperState(SVGClipPainter::ClipperNotApplied)
         , m_masker(nullptr)
 #if ENABLE(ASSERT)
         , m_applyClipMaskAndFilterIfNecessaryCalled(false)
 #endif
     { }
 
     ~SVGPaintContext();
 
-    PaintInfo& paintInfo() { return m_paintInfo; }
+    PaintInfo& paintInfo() { return m_filterPaintInfo ? *m_filterPaintInfo : m_paintInfo; }
 
     // Return true if these operations aren't necessary or if they are successfully applied.
     bool applyClipMaskAndFilterIfNecessary();
 
-    static void paintSubtree(GraphicsContext*, const LayoutObject*);
+    static void paintSubtree(GraphicsContext&, const LayoutObject*);
 
     // TODO(fs): This functions feels a bit misplaced (we don't want this to
     // turn into the new kitchen sink). Move it if a better location surfaces.
     static bool paintForLayoutObject(const PaintInfo&, const ComputedStyle&, const LayoutObject&, LayoutSVGResourceMode, SkPaint&, const AffineTransform* additionalPaintServerTransform = nullptr);
 
 private:
     void applyCompositingIfNecessary();
 
     // Return true if no clipping is necessary or if the clip is successfully applied.
     bool applyClipIfNecessary(SVGResources*);
 
     // Return true if no masking is necessary or if the mask is successfully applied.
     bool applyMaskIfNecessary(SVGResources*);
 
     // Return true if no filtering is necessary or if the filter is successfully applied.
     bool applyFilterIfNecessary(SVGResources*);
 
     bool isIsolationInstalled() const;
 
-    const LayoutObject* m_object;
+    const LayoutObject& m_object;
     PaintInfo m_paintInfo;
-    const PaintInfo* m_originalPaintInfo;
+    OwnPtr<PaintInfo> m_filterPaintInfo;

[Xianzhu, 2015/12/10 16:55:36]

We no longer allow changing the context field of PaintInfo because it's now a
reference. m_filterPaintInfo will override m_paintInfo when it is not null.

     LayoutSVGResourceFilter* m_filter;
     LayoutSVGResourceClipper* m_clipper;
     SVGClipPainter::ClipperState m_clipperState;
     LayoutSVGResourceMasker* m_masker;
     OwnPtr<CompositingRecorder> m_compositingRecorder;
     OwnPtr<ClipPathRecorder> m_clipPathRecorder;
     OwnPtr<SVGFilterRecordingContext> m_filterRecordingContext;
 #if ENABLE(ASSERT)
     bool m_applyClipMaskAndFilterIfNecessaryCalled;
 #endif
 };
 
 } // namespace blink
 
 #endif // SVGPaintContext_h