I'm expanding this to fix a couple of bugs in determining the file name for...

third_party/WebKit/WebCore/platform/chromium/ClipboardChromium.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2008, 2009 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 250 matching lines @@
     SharedBuffer* imageBuffer = cachedImage->image()->data();
     if (!imageBuffer || !imageBuffer->size())
         return;
 
     dataObject->fileContent = imageBuffer;
 
     // Determine the filename for the file contents of the image.  We try to
     // use the alt tag if one exists, otherwise we fall back on the suggested
     // filename in the http header, and finally we resort to using the filename
     // in the URL.
-    dataObject->fileExtension = ".";
-    dataObject->fileExtension += MIMETypeRegistry::getPreferredExtensionForMIMEType(
+    String extension = MIMETypeRegistry::getPreferredExtensionForMIMEType(
         cachedImage->response().mimeType());
+    dataObject->fileExtension = extension.isEmpty() ? "" : "." + extension;
     String title = element->getAttribute(altAttr);
-    if (title.isEmpty()) {
+    if (title.isEmpty())
         title = cachedImage->response().suggestedFilename();
-    }
+
+    title = ClipboardChromium::validateFileName(title, dataObject);
     dataObject->fileContentFilename = title + dataObject->fileExtension;
 }
 
 void ClipboardChromium::declareAndWriteDragImage(Element* element, const KURL& url, const String& title, Frame* frame)
 {
     if (!m_dataObject)
         return;
 
     m_dataObject->url = url;
     m_dataObject->urlTitle = title;
@@ skipping 48 matching lines @@
 
 bool ClipboardChromium::hasData()
 {
     if (!m_dataObject)
         return false;
 
     return m_dataObject->hasData();
 }
 
 } // namespace WebCore