Append software rendering list version to the about:gpu page.

chrome/browser/gpu_data_manager.h

Index: chrome/browser/gpu_data_manager.h
===================================================================
--- chrome/browser/gpu_data_manager.h	(revision 80377)
+++ chrome/browser/gpu_data_manager.h	(working copy)
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <set>
+#include <string>
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
@@ -37,6 +38,8 @@
   // if not blacklisted. Caller is responsible for deleting returned value.
   Value* GetBlacklistingReasons() const;
 
+  std::string GetBlacklistVersion() const;
+
   void AddLogMessage(Value* msg);
 
   const ListValue& log_messages() const;