Fixed WebDragData's wrong dependency.

Source/core/clipboard/DataObject.h

Index: Source/core/clipboard/DataObject.h
diff --git a/Source/core/clipboard/DataObject.h b/Source/core/clipboard/DataObject.h
index b0c1d5f5c906546ee32cb048b5ca59b49c8e18d9..bba46a9cae57d44ea906ce0d1fe9dcac3bdbb487 100644
--- a/Source/core/clipboard/DataObject.h
+++ b/Source/core/clipboard/DataObject.h
@@ -46,6 +46,7 @@ namespace blink {
 
 class KURL;
 class SharedBuffer;
+class WebDragData;
 
 // A data object for holding data that would be in a clipboard or moved
 // during a drag-n-drop operation. This is the data that WebCore is aware
@@ -55,6 +56,7 @@ class DataObject : public RefCountedWillBeGarbageCollectedFinalized<DataObject>,
 public:
     static PassRefPtrWillBeRawPtr<DataObject> createFromPasteboard(PasteMode);
     static PassRefPtrWillBeRawPtr<DataObject> create();
+    static PassRefPtrWillBeRawPtr<DataObject> create(WebDragData);
 
     virtual ~DataObject();
 
@@ -97,6 +99,8 @@ public:
 
     DECLARE_TRACE();
 
+    WebDragData toWebDragData();
+
 private:
     DataObject();