node.cloneNode() should clone the value of file upload elements

Source/core/html/forms/FileInputType.cpp

Index: Source/core/html/forms/FileInputType.cpp
diff --git a/Source/core/html/forms/FileInputType.cpp b/Source/core/html/forms/FileInputType.cpp
index 2fbd187fe9f51f9b7b297f30372ee804a9904432..bfe8515a50cc45ee5669633de17388bd250fe0a0 100644
--- a/Source/core/html/forms/FileInputType.cpp
+++ b/Source/core/html/forms/FileInputType.cpp
@@ -360,6 +360,17 @@ String FileInputType::droppedFileSystemId()
     return m_droppedFileSystemId;
 }
 
+void FileInputType::copyFiles(PassRefPtrWillBeRawPtr<FileList> files)
+{
+    RefPtrWillBeRawPtr<FileList> fileList(FileList::create());
+    unsigned size = files->length();
+    for (unsigned i = 0; i < size; ++i) {
+        File* file = files->item(i);
+        fileList->append(File::createWithRelativePath(file->path(), file->webkitRelativePath()));
+    }
+    setFiles(fileList.release());
+}
+
 String FileInputType::defaultToolTip() const
 {
     FileList* fileList = m_fileList.get();