SVGTests should not leave detached elements in the tree

Source/core/svg/SVGElementRareData.h

Index: Source/core/svg/SVGElementRareData.h
diff --git a/Source/core/svg/SVGElementRareData.h b/Source/core/svg/SVGElementRareData.h
index 6f3b38da8d134059b54262e2ce5d9d33d4fe2b76..de57c1fc4e4cf58b7f127081c6fd908ac3d93036 100644
--- a/Source/core/svg/SVGElementRareData.h
+++ b/Source/core/svg/SVGElementRareData.h
@@ -43,6 +43,7 @@ public:
         , m_instancesUpdatesBlocked(false)
         , m_useOverrideComputedStyle(false)
         , m_needsOverrideComputedStyleUpdate(false)
+        , m_isValid(true)
     {
     }
 
@@ -74,6 +75,9 @@ public:
     CSSCursorImageValue* cursorImageValue() const { return m_cursorImageValue; }
     void setCursorImageValue(CSSCursorImageValue* cursorImageValue) { m_cursorImageValue = cursorImageValue; }
 
+    bool isValid() const { return m_isValid; }

[pdr., 2013/10/25 06:13:12]

I'm worried this name will confuse us in the future because it's pretty generic
and overloaded.

Could we go with something more descriptive here such as isValidForSVGTests and
isSVGTestsValidityCached?

+    void setIsValid(bool value) { m_isValid = value; }
+
     MutableStylePropertySet* animatedSMILStyleProperties() const { return m_animatedSMILStyleProperties.get(); }
     MutableStylePropertySet* ensureAnimatedSMILStyleProperties()
     {
@@ -113,6 +117,7 @@ private:
     bool m_instancesUpdatesBlocked : 1;
     bool m_useOverrideComputedStyle : 1;
     bool m_needsOverrideComputedStyleUpdate : 1;
+    bool m_isValid : 1;
     RefPtr<MutableStylePropertySet> m_animatedSMILStyleProperties;
     RefPtr<RenderStyle> m_overrideComputedStyle;
 };