[Mac] Implement the system dictionary popup by implementing NSTextInput methods.

chrome/browser/renderer_host/render_widget_host_view_gtk.h

 // Copyright (c) 2011 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_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #pragma once
 
 #include <gdk/gdk.h>
 
@@ skipping 64 matching lines @@
                                        const gfx::Rect& caret_rect);
   virtual void ImeCancelComposition();
   virtual void DidUpdateBackingStore(
       const gfx::Rect& scroll_rect, int scroll_dx, int scroll_dy,
       const std::vector<gfx::Rect>& copy_rects);
   virtual void RenderViewGone(base::TerminationStatus status,
                               int error_code);
   virtual void Destroy();
   virtual void WillDestroyRenderWidget(RenderWidgetHost* rwh) {}
   virtual void SetTooltipText(const std::wstring& tooltip_text);
-  virtual void SelectionChanged(const std::string& text);
+  virtual void SelectionChanged(const std::string& text, int start, int end);
   virtual void ShowingContextMenu(bool showing);
   virtual BackingStore* AllocBackingStore(const gfx::Size& size);
   virtual void SetBackground(const SkBitmap& background);
   virtual void CreatePluginContainer(gfx::PluginWindowHandle id);
   virtual void DestroyPluginContainer(gfx::PluginWindowHandle id);
   virtual void SetVisuallyDeemphasized(const SkColor* color, bool animate);
   virtual bool ContainsNativeView(gfx::NativeView native_view) const;
   virtual void AcceleratedCompositingActivated(bool activated);
 
   // ui::AnimationDelegate implementation.
@@ skipping 128 matching lines @@
   // indicate the top edge, positive the bottom.
   int dragged_at_vertical_edge_;
 
 #if defined(OS_CHROMEOS)
   // Custimized tooltip window.
   scoped_ptr<views::TooltipWindowGtk> tooltip_window_;
 #endif  // defined(OS_CHROMEOS)
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_