Implemented Document.contentType

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 0cfd6712f3b22b0ea5b416b9d4c44deea5559b68..4c752e2cabba2458eb485bb28edc54d037a74e0f 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -353,6 +353,8 @@ public:
     void setContent(const String&);
 
     String suggestedMIMEType() const;
+    void setMimeType(const AtomicString&);
+    AtomicString contentType() const; // DOM 4 document.contentType
 
     const AtomicString& contentLanguage() const { return m_contentLanguage; }
     void setContentLanguage(const AtomicString&);
@@ -1185,6 +1187,9 @@ private:
 
     AtomicString m_baseTarget;
 
+    // Mime-type of the document in case it was cloned or created by XHR.
+    AtomicString m_mimeType;
+
     RefPtr<DocumentType> m_docType;
     OwnPtr<DOMImplementation> m_implementation;