Add a WebDocument::watchCssSelectors(selectors)

Source/core/rendering/style/StyleRareNonInheritedData.h

Index: Source/core/rendering/style/StyleRareNonInheritedData.h
diff --git a/Source/core/rendering/style/StyleRareNonInheritedData.h b/Source/core/rendering/style/StyleRareNonInheritedData.h
index bf42f5443f6345ae70e3af502eb2f7d4576447e2..272aa161a8f7c4a79d35614b1dc59e463867dad3 100644
--- a/Source/core/rendering/style/StyleRareNonInheritedData.h
+++ b/Source/core/rendering/style/StyleRareNonInheritedData.h
@@ -37,10 +37,12 @@
 #include "wtf/OwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/Vector.h"
+#include "wtf/WeakPtr.h"
 
 namespace WebCore {
 
 class CSSAnimationDataList;
+class Document;
 class ShadowData;
 class StyleDeprecatedFlexibleBoxData;
 class StyleFilterData;
@@ -143,6 +145,11 @@ public:
 
     int m_order;
 
+#if ENABLE(CSS_CALLBACKS)
+    Vector<String> m_callbackSelectors;
+    WeakPtr<Document> m_document;

[esprehn, 2013/07/13 01:43:01]

This doesn't look right, why do you have a document pointer down here? Also
StyleRareNonInheritedData is huge, an extension could easily end up adding it to
every style this way. ex. doing "div" to show up on every page.

Why do you need the m_document ptr here? All RenderStyle objects are tied to a
specific document anyway and so is the SelectorChecker and the StyleResolver. I
don't think you need those document checks

+#endif
+
     AtomicString m_flowThread;
     AtomicString m_regionThread;
     unsigned m_regionFragment : 1; // RegionFragment