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
diff --git a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
index 1ea942bff690ca4024f19a338c1ac7a23b7892e9..f396d12b6d32e9109c770657441e4cc8ddbc675e 100644
--- a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
+++ b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
@@ -37,6 +37,7 @@
 #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"
@@ -591,6 +592,14 @@ void ChromeResourceDispatcherHostDelegate::OnResponseStarted(
     }
   }
 
+  // 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);
 }