Use WebFrame::replaceMisspelledRange() to replace a misspelled range with text.

chrome/renderer/spellchecker/spellcheck_provider.h

 // 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.
 
 #ifndef CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_PROVIDER_H_
 #define CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_PROVIDER_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 59 matching lines @@
   virtual void requestCheckingOfText(
       const WebKit::WebString& text,
       WebKit::WebTextCheckingCompletion* completion) OVERRIDE;
   virtual WebKit::WebString autoCorrectWord(
       const WebKit::WebString& misspelled_word) OVERRIDE;
   virtual void showSpellingUI(bool show) OVERRIDE;
   virtual bool isShowingSpellingUI() OVERRIDE;
   virtual void updateSpellingUIWithMisspelledWord(
       const WebKit::WebString& word) OVERRIDE;
 
+  // Replaces the misspelling range that covers the cursor with the specified
+  // text. This function does not do anything if there are not any misspelling
+  // ranges that covers the cursor.
+  void OnReplace(const string16& text);
+
 #if !defined(OS_MACOSX)
   void OnRespondSpellingService(
       int identifier,
       int offset,
       bool succeeded,
       const string16& text,
       const std::vector<SpellCheckResult>& results);
 
   // Returns whether |text| has word characters, i.e. whether a spellchecker
   // needs to check this text.
@@ skipping 33 matching lines @@
   bool spelling_panel_visible_;
 
   // The ChromeContentRendererClient used to access the SpellChecker.
   // Weak reference.
   chrome::ChromeContentRendererClient* chrome_content_renderer_client_;
 
   DISALLOW_COPY_AND_ASSIGN(SpellCheckProvider);
 };
 
 #endif  // CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_PROVIDER_H_