Move 'designMode' attribute from HTMLDocument to Document

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 78528d6ab6762d5014ae714718921f8a75c17f52..00d6d6d9be62749306919b292a345416189273c2 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -4352,6 +4352,23 @@ bool Document::inDesignMode() const
     return false;
 }
 
+String Document::designMode() const
+{
+    return inDesignMode() ? "on" : "off";
+}
+
+void Document::setDesignMode(const String& value)
+{
+    InheritedBool mode;
+    if (equalIgnoringCase(value, "on"))
+        mode = on;
+    else if (equalIgnoringCase(value, "off"))
+        mode = off;
+    else
+        mode = inherit;
+    setDesignMode(mode);
+}
+
 Document* Document::parentDocument() const
 {
     if (!m_frame)