Implement a shell of FindRequestManager, and hook it up to WebContentsImpl.

extensions/browser/guest_view/web_view/web_view_find_helper.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 "extensions/browser/guest_view/web_view/web_view_find_helper.h"
 
 #include <utility>
 
 #include "components/guest_view/browser/guest_view_event.h"
 #include "extensions/browser/api/guest_view/web_view/web_view_internal_api.h"
@@ skipping 139 matching lines @@
   FindInfoMap::iterator find_iterator = find_info_map_.find(request_id);
 
   // Ignore slow replies to canceled find requests.
   if (find_iterator == find_info_map_.end())
     return;
 
   // This find request must be a part of an existing find session.
   DCHECK(current_find_session_);
 
   WebViewFindHelper::FindInfo* find_info = find_iterator->second.get();
-
   // Handle canceled find requests.
   if (!find_info->options()->findNext &&
       find_info_map_.begin()->first < request_id) {
     DCHECK_NE(current_find_session_->request_id(),
               find_info_map_.begin()->first);
-    DispatchFindUpdateEvent(true /* canceled */, true /* final_update */);
+    if (find_update_event_)
+      DispatchFindUpdateEvent(true /* canceled */, true /* final_update */);
     EndFindSession(find_info_map_.begin()->first, true /* canceled */);
   }
 
   // Clears the results for |findupdate| for a new find session.
   if (!find_info->replied() && !find_info->options()->findNext)
     find_update_event_.reset(new FindUpdateEvent(find_info->search_text()));
 
   // Aggregate the find results.
   find_info->AggregateResults(number_of_matches, selection_rect,
                               active_match_ordinal, final_update);
@@ skipping 104 matching lines @@
   results.SetBoolean(webview::kFindCanceled, canceled);
 
   // Call the callback.
   find_function_->SetResult(results.DeepCopy());
   find_function_->SendResponse(true);
 }
 
 WebViewFindHelper::FindInfo::~FindInfo() {}
 
 }  // namespace extensions