mac: Don't reference nav.pdf from TabView.xib

chrome/app/nibs/TabView.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">10K540</string>
-                <string key="IBDocument.InterfaceBuilderVersion">804</string>
+                <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>
-                        <string key="NS.object.0">804</string>
+                        <string key="NS.object.0">851</string>
                 </object>
                 <object class="NSMutableArray" key="IBDocument.EditedObjectIDs">
                         <bool key="EncodedWithXMLCoder">YES</bool>
                         <integer value="1"/>
                 </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">
@@ skipping 35 matching lines @@
                                                                 <string>NeXT Encapsulated PostScript v1.2 pasteboard type</string>
                                                                 <string>NeXT TIFF v4.0 pasteboard type</string>
                                                         </object>
                                                 </object>
                                                 <string key="NSFrame">{{18, 5}, {16, 16}}</string>
                                                 <reference key="NSSuperview" ref="1005"/>
                                                 <bool key="NSEnabled">YES</bool>
                                                 <object class="NSImageCell" key="NSCell" id="1061639670">
                                                         <int key="NSCellFlags">537001472</int>
                                                         <int key="NSCellFlags2">33587200</int>
-                                                        <object class="NSCustomResource" key="NSContents">
-                                                                <string key="NSClassName">NSImage</string>
-                                                                <string key="NSResourceName">nav</string>
-                                                        </object>
                                                         <int key="NSAlign">0</int>
                                                         <int key="NSScale">2</int>
                                                         <int key="NSStyle">0</int>
                                                         <bool key="NSAnimates">NO</bool>
                                                 </object>
                                                 <bool key="NSEditable">YES</bool>
                                         </object>
                                         <object class="NSButton" id="1054640993">
                                                 <reference key="NSNextResponder" ref="1005"/>
                                                 <int key="NSvFlags">297</int>
@@ skipping 1182 matching lines @@
                         <string key="NS.key.0">com.apple.InterfaceBuilder.CocoaPlugin.macosx</string>
                         <integer value="1050" key="NS.object.0"/>
                 </object>
                 <object class="NSMutableDictionary" key="IBDocument.PluginDeclaredDevelopmentDependencies">
                         <string key="NS.key.0">com.apple.InterfaceBuilder.CocoaPlugin.InterfaceBuilder3</string>
                         <integer value="3000" key="NS.object.0"/>
                 </object>
                 <bool key="IBDocument.PluginDeclaredDependenciesTrackSystemTargetVersion">YES</bool>
                 <string key="IBDocument.LastKnownRelativeProjectPath">../../chrome.xcodeproj</string>
                 <int key="IBDocument.defaultPropertyAccessControl">3</int>
-                <object class="NSMutableDictionary" key="IBDocument.LastKnownImageSizes">
-                        <string key="NS.key.0">nav</string>
-                        <string key="NS.object.0">{16, 16}</string>
-                </object>
         </data>
 </archive>