Fix crash when using remote DevTools on CrOS WebUI - check for response_headers

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 c1f959b5bbf429475f1ffcad6347237098852c04..cf9c367f95f4fd850a62892d2b82a589c231582b 100644
--- a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
+++ b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
@@ -662,7 +662,7 @@ void ChromeResourceDispatcherHostDelegate::OnResponseStarted(
   if (request_spec == chrome::kChromeUIChromeSigninURL) {
 #endif
     net::HttpResponseHeaders* response_headers = request->response_headers();
-    if (response_headers->HasHeader("x-frame-options"))
+    if (response_headers && response_headers->HasHeader("x-frame-options"))
       response_headers->RemoveHeader("x-frame-options");
   }