FrameTree::Find only searches relative to local frames.

components/printing/test/print_web_view_helper_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/printing/renderer/print_web_view_helper.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <tuple>
@@ skipping 395 matching lines @@
       "  frames['sub1'].document.write("
       "      '<p>Cras tempus ante eu felis semper luctus!</p>');"
       "  frames['sub1'].document.close();"
       "</script></body></html>";
 
   LoadHTML(html);
 
   // Find the frame and set it as the focused one.  This should mean that that
   // the printout should only contain the contents of that frame.
   auto* web_view = view_->GetWebView();
-  WebFrame* sub1_frame = web_view->FindFrameByName(WebString::FromUTF8("sub1"));
+  WebFrame* sub1_frame =
+      web_view->MainFrame()->ToWebLocalFrame()->FindFrameByName(
+          WebString::FromUTF8("sub1"));
   ASSERT_TRUE(sub1_frame);
   web_view->SetFocusedFrame(sub1_frame);
   ASSERT_NE(web_view->FocusedFrame(), web_view->MainFrame());
 
   // Initiate printing.
   OnPrintPages();
   VerifyPagesPrinted(true);
 
   // Verify output through MockPrinter.
   const MockPrinter* printer(print_render_thread_->printer());
@@ skipping 727 matching lines @@
 
   VerifyPrintFailed(true);
   VerifyPagesPrinted(false);
 }
 #endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 #endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
 
 #endif  // !defined(OS_CHROMEOS)
 
 }  // namespace printing