Make Edit>Speech>Speak Selection work for PDFs on Mac

content/public/browser/browser_plugin_guest_manager.cc

 // Copyright 2014 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 "content/public/browser/browser_plugin_guest_manager.h"
 
 namespace content {
 
 WebContents* BrowserPluginGuestManager::GetGuestByInstanceID(
     int owner_process_id,
     int browser_plugin_instance_id) {
   return nullptr;
 }
 
 bool BrowserPluginGuestManager::ForEachGuest(
     WebContents* embedder_web_contents,
     const GuestCallback& callback) {
   return false;
 }
 
+WebContents* BrowserPluginGuestManager::GetFullPageGuest(
+    WebContents* embedder_web_contents) {
+  return nullptr;
+}
+
 }  // content