Initial PaintInvalidationState support for SVG

Source/core/rendering/PaintInvalidationState.h

Index: Source/core/rendering/PaintInvalidationState.h
diff --git a/Source/core/rendering/PaintInvalidationState.h b/Source/core/rendering/PaintInvalidationState.h
index dcca3932f86641d1850efd77b6424936e3a584f3..7eb8f4c8f6134327bd7b754f61b9c502ffbd5462 100644
--- a/Source/core/rendering/PaintInvalidationState.h
+++ b/Source/core/rendering/PaintInvalidationState.h
@@ -6,23 +6,27 @@
 #define PaintInvalidationState_h
 
 #include "platform/geometry/LayoutRect.h"
+#include "platform/transforms/AffineTransform.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class RenderLayerModelObject;
 class RenderObject;
+class RenderSVGModelObject;
 class RenderView;
 
 class PaintInvalidationState {
     WTF_MAKE_NONCOPYABLE(PaintInvalidationState);
 public:
     PaintInvalidationState(const PaintInvalidationState& next, RenderLayerModelObject& renderer, const RenderLayerModelObject& paintInvalidationContainer);
+    PaintInvalidationState(const PaintInvalidationState& next, const RenderSVGModelObject& renderer);
 
     explicit PaintInvalidationState(const RenderView&);
 
     const LayoutRect& clipRect() const { return m_clipRect; }
     const LayoutSize& paintOffset() const { return m_paintOffset; }
+    const AffineTransform& svgTransform() const { return m_svgTransform; }
 
     bool cachedOffsetsEnabled() const { return m_cachedOffsetsEnabled; }
     bool isClipped() const { return m_clipped; }
@@ -38,6 +42,7 @@ public:
     }
 private:
     void applyClipIfNeeded(const RenderObject&);
+    void addClipRectRelativeToPaintOffset(const LayoutSize& clipSize);
 
     friend class ForceHorriblySlowRectMapping;
 
@@ -51,6 +56,11 @@ private:
     LayoutSize m_paintOffset;
 
     const RenderLayerModelObject& m_paintInvalidationContainer;
+
+    // Transform from the initial viewport coordinate system of an outermost
+    // SVG root to the userspace _before_ the relevant element. Combining this
+    // with |m_paintOffset| yields the "final" offset.
+    AffineTransform m_svgTransform;

[pdr., 2014/09/25 05:38:59]

Could we use an OwnPtr here to lazily allocate this?

[fs, 2014/09/25 12:17:53]

Yes, I suppose that could be a reasonable compromise (it makes the
initialization a bit more unwieldy though.) Done.

 };
 
 } // namespace blink