Add a Dns preresolve interface in //content

chrome/browser/chromeos/login/helper.h

Index: chrome/browser/chromeos/login/helper.h
diff --git a/chrome/browser/chromeos/login/helper.h b/chrome/browser/chromeos/login/helper.h
index c2d0d7f5b46ab69cd99b1fd4087d2c2062fc826f..c2039958f83be4a83c5e7f1da4f7f4a5ae11be3f 100644
--- a/chrome/browser/chromeos/login/helper.h
+++ b/chrome/browser/chromeos/login/helper.h
@@ -23,6 +23,7 @@ class Size;
 }  // namespace gfx
 
 namespace content {
+class ResourceContext;
 class StoragePartition;
 }
 
@@ -110,6 +111,8 @@ content::StoragePartition* GetSigninPartition();
 // flow, the context of the sign-in webview storage partition is returned.
 net::URLRequestContextGetter* GetSigninContext();
 
+content::ResourceContext* GetSigninResourceContext();
+
 }  // namespace login
 
 }  // namespace chromeos