Merge r205158 (SocketStream uses a weak ptr to URLRequestContext)

net/url_request/url_request_context.h

Index: net/url_request/url_request_context.h
===================================================================
--- net/url_request/url_request_context.h	(revision 207753)
+++ net/url_request/url_request_context.h	(working copy)
@@ -47,7 +47,8 @@
 // these member variables, since they may be shared. For the ones that aren't
 // shared, URLRequestContextStorage can be helpful in defining their storage.
 class NET_EXPORT URLRequestContext
-    : NON_EXPORTED_BASE(public base::NonThreadSafe) {
+    : NON_EXPORTED_BASE(public base::NonThreadSafe),
+      public base::SupportsWeakPtr<URLRequestContext> {
  public:
   URLRequestContext();
   virtual ~URLRequestContext();