Move Singleton and related structs to namespace base

net/url_request/url_request_job_manager.h

Index: net/url_request/url_request_job_manager.h
diff --git a/net/url_request/url_request_job_manager.h b/net/url_request/url_request_job_manager.h
index 7729abbbe2b710031367cd0f8fbc588b111ce2e1..422a9821636780f799bdb55840d802ccde1b77a4 100644
--- a/net/url_request/url_request_job_manager.h
+++ b/net/url_request/url_request_job_manager.h
@@ -11,7 +11,9 @@
 #include "net/base/net_export.h"
 #include "net/url_request/url_request.h"
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}  // namespace base
 
 namespace net {
 
@@ -51,7 +53,7 @@ class NET_EXPORT URLRequestJobManager {
   static bool SupportsScheme(const std::string& scheme);
 
  private:
-  friend struct DefaultSingletonTraits<URLRequestJobManager>;
+  friend struct base::DefaultSingletonTraits<URLRequestJobManager>;
 
   URLRequestJobManager();
   ~URLRequestJobManager();