ImageBuffer-less SVG masking and clipping.

Source/core/rendering/svg/RenderSVGResourceClipper.h

Index: Source/core/rendering/svg/RenderSVGResourceClipper.h
diff --git a/Source/core/rendering/svg/RenderSVGResourceClipper.h b/Source/core/rendering/svg/RenderSVGResourceClipper.h
index 69ee9865220a65a4369cf1da26cd3bbb93caf5be..7344e7eff60f9643a574e1de3a28fdd844878fe4 100644
--- a/Source/core/rendering/svg/RenderSVGResourceClipper.h
+++ b/Source/core/rendering/svg/RenderSVGResourceClipper.h
@@ -28,7 +28,11 @@ namespace WebCore {
 struct ClipperData {
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    OwnPtr<ImageBuffer> clipMaskImage;
+    enum ClipMode { PathOnlyClipMode, MaskClipMode };
+
+    // We should eventually cache the combined clip path here, when switching to path ops clipping.
+    // For now we only cache a marker to let postApply know whether it needs to perform any work.
+    ClipMode clipMode;
 };
 
 class RenderSVGResourceClipper FINAL : public RenderSVGResourceContainer {
@@ -41,11 +45,13 @@ public:
     virtual void removeAllClientsFromCache(bool markForInvalidation = true);
     virtual void removeClientFromCache(RenderObject*, bool markForInvalidation = true);
 
-    virtual bool applyResource(RenderObject*, RenderStyle*, GraphicsContext*&, unsigned short resourceMode);
+    virtual bool applyResource(RenderObject*, RenderStyle*, GraphicsContext*&, unsigned short resourceMode) OVERRIDE;
+    virtual void postApplyResource(RenderObject*, GraphicsContext*&, unsigned short, const Path*, const RenderSVGShape*) OVERRIDE;
     // clipPath can be clipped too, but don't have a boundingBox or repaintRect. So we can't call
     // applyResource directly and use the rects from the object, since they are empty for RenderSVGResources
     // FIXME: We made applyClippingToContext public because we cannot call applyResource on HTML elements (it asserts on RenderObject::objectBoundingBox)
     bool applyClippingToContext(RenderObject*, const FloatRect&, const FloatRect&, GraphicsContext*);
+
     virtual FloatRect resourceBoundingBox(RenderObject*);
 
     virtual RenderSVGResourceType resourceType() const { return ClipperResourceType; }
@@ -56,12 +62,15 @@ public:
 
     static RenderSVGResourceType s_resourceType;
 private:
-    bool pathOnlyClipping(GraphicsContext*, const AffineTransform&, const FloatRect&);
-    bool drawContentIntoMaskImage(ClipperData*, const FloatRect& objectBoundingBox);
+    bool tryPathOnlyClipping(GraphicsContext*, const AffineTransform&, const FloatRect&);
+    void drawMaskContent(GraphicsContext*, const FloatRect& targetBoundingBox);
     void calculateClipContentRepaintRect();
 
     FloatRect m_clipBoundaries;
-    HashMap<RenderObject*, ClipperData*> m_clipper;
+    HashMap<const RenderObject*, OwnPtr<ClipperData> > m_rendererToClipperMap;
+
+    // Reference cycle detection.
+    bool m_inClipExpansion;
 };
 
 }