Move small c/b/extensions classes into extensions namespace no.1

chrome/browser/extensions/autoupdate_interceptor.h

Index: chrome/browser/extensions/autoupdate_interceptor.h
diff --git a/chrome/browser/extensions/autoupdate_interceptor.h b/chrome/browser/extensions/autoupdate_interceptor.h
index 8fbcc3e6f9f958fc0b814b84180b4ffbb518b2cd..36dd7c94d73176177fc8f3d793130802914eb508 100644
--- a/chrome/browser/extensions/autoupdate_interceptor.h
+++ b/chrome/browser/extensions/autoupdate_interceptor.h
@@ -11,6 +11,8 @@
 #include "googleurl/src/gurl.h"
 #include "net/url_request/url_request.h"
 
+namespace extensions {
+
 // This url request interceptor lets us respond to localhost http request urls
 // with the contents of files on disk for use in tests.
 class AutoUpdateInterceptor
@@ -42,4 +44,6 @@ class AutoUpdateInterceptor
   DISALLOW_COPY_AND_ASSIGN(AutoUpdateInterceptor);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_AUTOUPDATE_INTERCEPTOR_H_