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

chrome/common/render_messages_internal.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.
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "build/build_config.h"
@@ skipping 1628 matching lines @@
 IPC_SYNC_MESSAGE_ROUTED1_1(ViewHostMsg_GetScreenInfo,
                            gfx::NativeViewId /* view */,
                            WebKit::WebScreenInfo /* results */)
 
 // Send the tooltip text for the current mouse position to the browser.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_SetTooltipText,
                     std::wstring /* tooltip text string */,
                     WebKit::WebTextDirection /* text direction hint */)
 
 // Notification that the text selection has changed.
-IPC_MESSAGE_ROUTED1(ViewHostMsg_SelectionChanged,
-                    std::string /* currently selected text */)
+IPC_MESSAGE_ROUTED3(ViewHostMsg_SelectionChanged,
+                    std::string /* currently selected text */,
+                    int /* selection range start */,
+                    int /* selection range end */)
 
 // Asks the browser to display the file chooser.  The result is returned in a
 // ViewHost_RunFileChooserResponse message.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_RunFileChooser,
                     ViewHostMsg_RunFileChooser_Params)
 
 // Used to tell the parent the user started dragging in the content area. The
 // WebDropData struct contains contextual information about the pieces of the
 // page the user dragged. The parent uses this notification to initiate a
 // drag session at the OS level.
@@ skipping 884 matching lines @@
 // while performing stress testing.
 IPC_MESSAGE_ROUTED2(ViewMsg_JavaScriptStressTestControl,
                     int /* cmd */,
                     int /* param */)
 
 // Register a new handler for URL requests with the given scheme.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_RegisterProtocolHandler,
                     std::string /* scheme */,
                     GURL /* url */,
                     string16 /* title */)