Prevent web content from forging File entries in drag and drop.

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 6c5e1cf10d82ade22630d2fcb25a0a2ec90ccbf9..247ca0f5bc62444928d015ec407cf0c27f4e9a95 100644
--- a/Source/core/clipboard/DataObject.h
+++ b/Source/core/clipboard/DataObject.h
@@ -91,6 +91,10 @@ public:
     int modifierKeyState() const { return m_modifierKeyState; }
     void setModifierKeyState(int modifierKeyState) { m_modifierKeyState = modifierKeyState; }
 
+    // The accessor should only ever be called by DragData.
+    const String& filenameForNavigation() const { return m_filenameForNavigation; }
+    void setFilenameForNavigation(const String& filename) { m_filenameForNavigation = filename; }
+
     // FIXME: oilpan: This trace() has to trace Supplementable.
     void trace(Visitor*);
 
@@ -104,6 +108,8 @@ private:
 
     WillBeHeapVector<RefPtrWillBeMember<DataObjectItem> > m_itemList;
 
+    String m_filenameForNavigation;
+
     // State of Shift/Ctrl/Alt/Meta keys.
     int m_modifierKeyState;
 };