Allow data URLs to trigger downloads, as they do in Firefox....

net/base/data_url.h

Index: net/base/data_url.h
===================================================================
--- net/base/data_url.h	(revision 68044)
+++ net/base/data_url.h	(working copy)
@@ -37,6 +37,9 @@
   // If the URL is malformed, then this method will return false, and its
   // output variables will remain unchanged.  On success, true is returned.
   //
+  // OPTIONAL: If |data| is NULL, then the <data> section will not be parsed
+  //           or validated.
+  //
   static bool Parse(const GURL& url,
                     std::string* mime_type,
                     std::string* charset,