First cut at UI for saving net_logs data into a temporary file on

chrome/browser/net/net_log_logger.h

Index: chrome/browser/net/net_log_logger.h
===================================================================
--- chrome/browser/net/net_log_logger.h	(revision 173622)
+++ chrome/browser/net/net_log_logger.h	(working copy)
@@ -32,6 +32,10 @@
   // Separate from constructor to enforce thread safety.
   void StartObserving(net::NetLog* net_log);
 
+  // Stops observing specified NetLog.  Must already be watching a NetLog.
+  // Separate from constructor to enforce thread safety.
+  void StopObserving(net::NetLog* net_log);
+
   // net::NetLog::ThreadSafeObserver implementation:
   virtual void OnAddEntry(const net::NetLog::Entry& entry) OVERRIDE;