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

chrome/browser/renderer_host/text_input_client_message_filter.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_TEXT_INPUT_CLIENT_MESSAGE_FILTER_H_
+#define CHROME_BROWSER_RENDERER_HOST_TEXT_INPUT_CLIENT_MESSAGE_FILTER_H_
+
+#include "chrome/browser/browser_message_filter.h"
+
+namespace gfx {
+class Rect;
+}
+
+// This is a browser-side message filter that lives on the IO thread to handle
+// replies to messages sent by the TextInputClientMac. See
+// chrome/browser/renderer_host/text_input_client_mac.h for more information.
+class TextInputClientMessageFilter : public BrowserMessageFilter {
+ public:
+  explicit TextInputClientMessageFilter(int child_id);
+  virtual ~TextInputClientMessageFilter();
+
+  // BrowserMessageFilter override:
+  virtual void OverrideThreadForMessage(const IPC::Message& message,
+                                        BrowserThread::ID* thread);
+  virtual bool OnMessageReceived(const IPC::Message& message,
+                                bool* message_was_ok);
+
+ private:
+  // IPC Message handlers:
+  void OnGotCharacterIndexForPoint(uint index);
+  void OnGotFirstRectForRange(const gfx::Rect& rect);
+  void OnGotStringFromRange(const string16& string);
+  void OnImeCompositionRangeChanged(const IPC::Message& msg,
+                                    int start,
+                                    int end);
+
+  // Child process id.
+  int child_process_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(TextInputClientMessageFilter);
+};
+
+#endif  // CHROME_BROWSER_RENDERER_HOST_TEXT_INPUT_CLIENT_MESSAGE_FILTER_H_