mac: Update menu item command IDs in MainMenu.xib.

chrome/app/nibs/MainMenu.xib

 <?xml version="1.0" encoding="UTF-8"?>
 <archive type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="7.10">
         <data>
                 <int key="IBDocument.SystemTarget">1050</int>
                 <string key="IBDocument.SystemVersion">10K549</string>
                 <string key="IBDocument.InterfaceBuilderVersion">851</string>
                 <string key="IBDocument.AppKitVersion">1038.36</string>
                 <string key="IBDocument.HIToolboxVersion">461.00</string>
                 <object class="NSMutableDictionary" key="IBDocument.PluginVersions">
                         <string key="NS.key.0">com.apple.InterfaceBuilder.CocoaPlugin</string>
@@ skipping 1103 matching lines @@
                                                                         <reference key="NSMixedImage" ref="549394948"/>
                                                                         <int key="NSTag">40012</int>
                                                                 </object>
                                                                 <object class="NSMenuItem" id="1008975930">
                                                                         <reference key="NSMenu" ref="835318025"/>
                                                                         <string key="NSTitle">^IDS_SHOW_EXTENSIONS_MAC</string>
                                                                         <string key="NSKeyEquiv"/>
                                                                         <int key="NSMnemonicLoc">2147483647</int>
                                                                         <reference key="NSOnImage" ref="353210768"/>
                                                                         <reference key="NSMixedImage" ref="549394948"/>
-                                                                        <int key="NSTag">40021</int>
+                                                                        <int key="NSTag">40022</int>
                                                                 </object>
                                                                 <object class="NSMenuItem" id="693413486">
                                                                         <reference key="NSMenu" ref="835318025"/>
                                                                         <string key="NSTitle">^IDS_TASK_MANAGER_MAC</string>
                                                                         <string key="NSKeyEquiv"/>
                                                                         <int key="NSMnemonicLoc">2147483647</int>
                                                                         <reference key="NSOnImage" ref="353210768"/>
                                                                         <reference key="NSMixedImage" ref="549394948"/>
                                                                         <int key="NSTag">40005</int>
                                                                 </object>
@@ skipping 60 matching lines @@
                                                                         <int key="NSTag">40008</int>
                                                                 </object>
                                                                 <object class="NSMenuItem" id="679532991">
                                                                         <reference key="NSMenu" ref="374024848"/>
                                                                         <string key="NSTitle">^IDS_HELP_MAC$IDS_PRODUCT_NAME</string>
                                                                         <string key="NSKeyEquiv">?</string>
                                                                         <int key="NSKeyEquivModMask">1048576</int>
                                                                         <int key="NSMnemonicLoc">2147483647</int>
                                                                         <reference key="NSOnImage" ref="353210768"/>
                                                                         <reference key="NSMixedImage" ref="549394948"/>
-                                                                        <int key="NSTag">40019</int>
+                                                                        <int key="NSTag">40020</int>
                                                                 </object>
                                                         </object>
                                                 </object>
                                         </object>
                                 </object>
                                 <string key="NSName">_NSMainMenu</string>
                         </object>
                         <object class="NSCustomObject" id="168151378">
                                 <string key="NSClassName">AppController</string>
                         </object>
@@ skipping 3054 matching lines @@
                                 <string>NSMenuMixedState</string>
                         </object>
                         <object class="NSMutableArray" key="dict.values">
                                 <bool key="EncodedWithXMLCoder">YES</bool>
                                 <string>{9, 8}</string>
                                 <string>{7, 2}</string>
                         </object>
                 </object>
         </data>
 </archive>