Revert 51877, since SpdyNetworkTransactionTest.CorruptFrameSessionError start...

net/proxy/proxy_resolver.h

Index: net/proxy/proxy_resolver.h
===================================================================
--- net/proxy/proxy_resolver.h	(revision 51891)
+++ net/proxy/proxy_resolver.h	(working copy)
@@ -74,10 +74,6 @@
   // no-op implementation.
   virtual void PurgeMemory() {}
 
-  // Optional shutdown code to be run before destruction. This is only used
-  // by the multithreaded runner to signal cleanup from origin thread
-  virtual void Shutdown() {}
-
  private:
   // Called to set the PAC script backend to use. If |pac_url| is invalid,
   // this is a request to use WPAD (auto detect). |pac_script| may be empty if