Add a keyboard shortcut for the download page on Mac

chrome/app/nibs/en.lproj/MainMenu.xib

 <?xml version="1.0" encoding="UTF-8"?>
 <archive type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="7.03">
         <data>
                 <int key="IBDocument.SystemTarget">1050</int>
                 <string key="IBDocument.SystemVersion">9J61</string>
                 <string key="IBDocument.InterfaceBuilderVersion">677</string>
                 <string key="IBDocument.AppKitVersion">949.46</string>
                 <string key="IBDocument.HIToolboxVersion">353.00</string>
                 <object class="NSMutableArray" key="IBDocument.EditedObjectIDs">
                         <bool key="EncodedWithXMLCoder">YES</bool>
-                        <integer value="296"/>
+                        <integer value="24"/>
                 </object>
                 <object class="NSArray" key="IBDocument.PluginDependencies">
                         <bool key="EncodedWithXMLCoder">YES</bool>
                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                 </object>
                 <object class="NSMutableDictionary" key="IBDocument.Metadata">
                         <bool key="EncodedWithXMLCoder">YES</bool>
                         <object class="NSArray" key="dict.sortedKeys">
                                 <bool key="EncodedWithXMLCoder">YES</bool>
                         </object>
@@ skipping 1003 matching lines @@
                                                                         <bool key="NSIsSeparator">YES</bool>
                                                                         <string key="NSTitle"/>
                                                                         <string key="NSKeyEquiv"/>
                                                                         <int key="NSMnemonicLoc">2147483647</int>
                                                                         <reference key="NSOnImage" ref="353210768"/>
                                                                         <reference key="NSMixedImage" ref="549394948"/>
                                                                 </object>
                                                                 <object class="NSMenuItem" id="238061183">
                                                                         <reference key="NSMenu" ref="835318025"/>
                                                                         <string key="NSTitle">Downloads</string>
-                                                                        <string key="NSKeyEquiv"/>
+                                                                        <string key="NSKeyEquiv">J</string>
+                                                                        <int key="NSKeyEquivModMask">1048576</int>
                                                                         <int key="NSMnemonicLoc">2147483647</int>
                                                                         <reference key="NSOnImage" ref="353210768"/>
                                                                         <reference key="NSMixedImage" ref="549394948"/>
                                                                         <int key="NSTag">40012</int>
                                                                 </object>
                                                                 <object class="NSMenuItem" id="299356726">
                                                                         <reference key="NSMenu" ref="835318025"/>
                                                                         <bool key="NSIsDisabled">YES</bool>
                                                                         <bool key="NSIsSeparator">YES</bool>
                                                                         <string key="NSTitle"/>
@@ skipping 1743 matching lines @@
                                         <reference ref="9"/>
                                         <string>{{608, 612}, {241, 103}}</string>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <reference ref="9"/>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <reference ref="9"/>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <reference ref="9"/>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <reference ref="9"/>
-                                        <string>{{858, 558}, {213, 163}}</string>
+                                        <string>{{933, 1202}, {213, 163}}</string>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <reference ref="9"/>
                                         <string>{{525, 802}, {197, 73}}</string>
                                         <string>{{530, 1365}, {535, 20}}</string>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <reference ref="9"/>
                                         <string>{74, 862}</string>
                                         <string>{{11, 977}, {478, 20}}</string>
                                         <string>com.apple.InterfaceBuilder.CocoaPlugin</string>
                                         <string>{{722, 1152}, {287, 213}}</string>
@@ skipping 206 matching lines @@
                                                 <string key="minorKey">browser/cocoa/tab_strip_model_observer_bridge.h</string>
                                         </object>
                                 </object>
                         </object>
                 </object>
                 <int key="IBDocument.localizationMode">0</int>
                 <string key="IBDocument.LastKnownRelativeProjectPath">../../../chrome.xcodeproj</string>
                 <int key="IBDocument.defaultPropertyAccessControl">3</int>
         </data>
 </archive>