Fix unused functions warnings on Linux.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index ba44dba706799c4aa9eec28c46c7c4007419375a..c3189c758f8fbd0807c210773a300fd919b8b265 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -487,17 +487,6 @@ Document::Document(const DocumentInit& initializer, DocumentClassFlags documentC
     m_lifecyle.advanceTo(DocumentLifecycle::Inactive);
 }
 
-static bool isAttributeOnAllOwners(const WebCore::QualifiedName& attribute, const WebCore::QualifiedName& prefixedAttribute, const HTMLFrameOwnerElement* owner)
-{
-    if (!owner)
-        return true;
-    do {
-        if (!(owner->hasAttribute(attribute) || owner->hasAttribute(prefixedAttribute)))
-            return false;
-    } while ((owner = owner->document().ownerElement()));
-    return true;
-}
-
 Document::~Document()
 {
     ASSERT(!renderer());