SVG: Items inserted into list should be made a tear-off.

Source/core/svg/SVGPathSegListTearOff.h

Index: Source/core/svg/SVGPathSegListTearOff.h
diff --git a/Source/core/svg/SVGPathSegListTearOff.h b/Source/core/svg/SVGPathSegListTearOff.h
index f360f34fca57a23e7a83fd95d0238573f0afad1c..da3046188e8292bbd3ca6be365b5af87aee5d7a9 100644
--- a/Source/core/svg/SVGPathSegListTearOff.h
+++ b/Source/core/svg/SVGPathSegListTearOff.h
@@ -31,6 +31,7 @@
 #ifndef SVGPathSegListTearOff_h
 #define SVGPathSegListTearOff_h
 
+#include "SVGNames.h"
 #include "core/svg/SVGPathSegList.h"
 #include "core/svg/properties/SVGListPropertyTearOffHelper.h"
 
@@ -43,9 +44,12 @@ public:
     // FIXME: Currently SVGPathSegitself is a tear-off.
     typedef SVGPathSeg ItemTearOffType;
 
-    static PassRefPtr<ItemPropertyType> getValueForInsertionFromTearOff(PassRefPtr<ItemTearOffType> passNewItem)
+    static PassRefPtr<ItemPropertyType> getValueForInsertionFromTearOff(PassRefPtr<ItemTearOffType> passNewItem, SVGElement* contextElement, const QualifiedName& attributeName)
     {
-        return passNewItem;
+        ASSERT(attributeName == SVGNames::dAttr);
+        RefPtr<ItemTearOffType> newItem = passNewItem;
+        newItem->setContextElement(contextElement);

[Erik Dahlström (inactive), 2014/06/11 08:31:32]

Doesn't this need to set attributeName too? Like if you move a pathseglist from
an animateMotion element to a path element for example ("path" to "d"
attribute). Please add a test like that. Does it also need to update the
PropertyIsAnimValType flag?

[kouhei (in TOK), 2014/06/12 04:25:28]

I think this is correct. SVGAnimateMotionElement do not expose DOM (both in
SVG{1.1,2} spec and in Blink impl), so the only attributeName is dAttr.

[Erik Dahlström (inactive), 2014/06/12 08:47:04]

Fair enough for pathseglist then, but the other lists share the same issue.
Let's say you move an SVGLength from an x to an y attribute for example.

+        return newItem.release();
     }
 
     static PassRefPtr<ItemTearOffType> createTearOff(PassRefPtr<ItemPropertyType> passValue, SVGElement* contextElement, PropertyIsAnimValType, const QualifiedName&)