Revert 251503 "Implement inline signin with iframe"

chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc

Index: chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
===================================================================
--- chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc	(revision 251944)
+++ chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc	(working copy)
@@ -38,7 +38,6 @@
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/mime_types_handler.h"
 #include "chrome/common/render_messages.h"
-#include "chrome/common/url_constants.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_process_host.h"
@@ -613,14 +612,6 @@
     }
   }
 
-  // Ignores x-frame-options for the chrome signin UI.
-  if (request->first_party_for_cookies().GetOrigin().spec() ==
-      chrome::kChromeUIChromeSigninURL) {
-    net::HttpResponseHeaders* response_headers = request->response_headers();
-    if (response_headers->HasHeader("x-frame-options"))
-      response_headers->RemoveHeader("x-frame-options");
-  }
-
   prerender::URLRequestResponseStarted(request);
 }