Remove selected text when committing empty text

third_party/WebKit/Source/web/WebLocalFrameImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1283 matching lines @@
 bool WebLocalFrameImpl::SetCompositionFromExistingText(
     int composition_start,
     int composition_end,
     const WebVector<WebCompositionUnderline>& underlines) {
   TRACE_EVENT0("blink", "WebLocalFrameImpl::setCompositionFromExistingText");
   if (!GetFrame()->GetEditor().CanEdit())
     return false;
 
   InputMethodController& input_method_controller =
       GetFrame()->GetInputMethodController();
-  input_method_controller.CancelComposition();
-
-  if (composition_start == composition_end)
-    return true;
 
   // TODO(editing-dev): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited.  See http://crbug.com/590369 for more details.
   GetFrame()->GetDocument()->UpdateStyleAndLayoutIgnorePendingStylesheets();
 
   input_method_controller.SetCompositionFromExistingText(
       CompositionUnderlineVectorBuilder::Build(underlines), composition_start,
       composition_end);
 
   return true;
@@ skipping 1258 matching lines @@
 TextCheckerClient& WebLocalFrameImpl::GetTextCheckerClient() const {
   return *text_checker_client_;
 }
 
 void WebLocalFrameImpl::SetTextCheckClient(
     WebTextCheckClient* text_check_client) {
   text_check_client_ = text_check_client;
 }
 
 }  // namespace blink