Add a WebDocument::watchCssSelectors(selectors)

Source/core/rendering/style/RenderStyle.cpp

Index: Source/core/rendering/style/RenderStyle.cpp
diff --git a/Source/core/rendering/style/RenderStyle.cpp b/Source/core/rendering/style/RenderStyle.cpp
index a48257fdfa04ec7ca1520c628dd7a1e98e6c0649..9cebcfbd524ed53e80fff81cd46e215c674bd337 100644
--- a/Source/core/rendering/style/RenderStyle.cpp
+++ b/Source/core/rendering/style/RenderStyle.cpp
@@ -691,6 +691,30 @@ void RenderStyle::clearCursorList()
         rareInheritedData.access()->cursorData = 0;
 }
 
+#if ENABLE(CSS_CALLBACKS)
+void RenderStyle::addCallbackSelector(const String& selector, Document* document)
+{
+    ASSERT(!rareNonInheritedData->m_document.get()
+        || rareNonInheritedData->m_document.get() == document);
+    if (!rareNonInheritedData->m_callbackSelectors.contains(selector)) {
+        StyleRareNonInheritedData* data = rareNonInheritedData.access();
+        data->m_callbackSelectors.append(selector);
+        // Assigns a WeakPtr to |document| to data->m_document.
+        document->addSelectorMatch(selector, data);
+    }
+}
+
+void RenderStyle::removeCallbackSelector(const String& selector)
+{
+    size_t index = rareNonInheritedData->m_callbackSelectors.find(selector);
+    if (index != notFound) {
+        rareNonInheritedData.access()->m_callbackSelectors.remove(index);
+        if (Document* document = rareNonInheritedData->m_document.get())
+            document->removeSelectorMatch(selector);
+    }
+}
+#endif
+
 void RenderStyle::clearContent()
 {
     if (rareNonInheritedData->m_content)