Add a WebDocument::watchCssSelectors(selectors)

Source/core/rendering/style/RenderStyle.h

Index: Source/core/rendering/style/RenderStyle.h
diff --git a/Source/core/rendering/style/RenderStyle.h b/Source/core/rendering/style/RenderStyle.h
index ce0e7524c9c1aa964f19625bee9c92eac4327fcd..8f4b283a30696772c6081c1e530eb7dd07f74c45 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -728,6 +728,7 @@ public:
     EBoxPack boxPack() const { return static_cast<EBoxPack>(rareNonInheritedData->m_deprecatedFlexibleBox->pack); }
 
     int order() const { return rareNonInheritedData->m_order; }
+    const Vector<String>& callbackSelectors() const { return rareNonInheritedData->m_callbackSelectors; }
     float flexGrow() const { return rareNonInheritedData->m_flexibleBox->m_flexGrow; }
     float flexShrink() const { return rareNonInheritedData->m_flexibleBox->m_flexShrink; }
     Length flexBasis() const { return rareNonInheritedData->m_flexibleBox->m_flexBasis; }
@@ -1188,6 +1189,7 @@ public:
     void setFlexShrink(float f) { SET_VAR(rareNonInheritedData.access()->m_flexibleBox, m_flexShrink, f); }
     void setFlexBasis(Length length) { SET_VAR(rareNonInheritedData.access()->m_flexibleBox, m_flexBasis, length); }
     void setOrder(int o) { SET_VAR(rareNonInheritedData, m_order, o); }
+    void addCallbackSelector(const String& selector);
     void setAlignContent(EAlignContent p) { SET_VAR(rareNonInheritedData, m_alignContent, p); }
     void setAlignItems(EAlignItems a) { SET_VAR(rareNonInheritedData, m_alignItems, a); }
     void setAlignSelf(EAlignItems a) { SET_VAR(rareNonInheritedData, m_alignSelf, a); }