don't show dart menu for non dart projects

editor/tools/plugins/com.google.dart.eclipse.ui/plugin.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <?eclipse version="3.4"?>
 <plugin>
    <extension
          point="org.eclipse.ui.newWizards">
       <category
             id="com.google.dart.eclipse.wizards.projects"
             name="Dart">
       </category>
       
@@ skipping 274 matching lines @@
                     <test
                           property="com.google.dart.eclipse.ui.isInPubCache"
                           value="false"/>
                 </adapt>
             </and>
         </filterExpression>
     </commonFilter>
    </extension>
    <extension
         point="org.eclipse.ui.navigator.viewer">
+     <viewerContentBinding viewerId="org.eclipse.jdt.ui.PackageExplorer">
+        <includes>
+           <contentExtension 
+              pattern="com.google.dart.eclipse.ui.navigatorContent">
+           </contentExtension>
+           <contentExtension
+              pattern="com.google.dart.eclipse.ui.commonFilter.pubCacheProjects">
+           </contentExtension>
+        </includes>
+     </viewerContentBinding>
+   </extension>
+
+ <extension
+        point="org.eclipse.ui.navigator.viewer">
      <viewerContentBinding viewerId="org.eclipse.ui.navigator.ProjectExplorer">
         <includes>
            <contentExtension 
               pattern="com.google.dart.eclipse.ui.navigatorContent">
            </contentExtension>
            <contentExtension
               pattern="com.google.dart.eclipse.ui.commonFilter.pubCacheProjects">
            </contentExtension>
         </includes>
      </viewerContentBinding>
    </extension>
-
+   
   <extension point="org.eclipse.ui.menus">
    <menuContribution
             locationURI="toolbar:org.eclipse.ui.main.toolbar?after=additions">
          <toolbar
                id="com.google.dart.tools.server.toolbar"
                label="Analysis Server Status Toolbar Addition">
             <control
                class="com.google.dart.tools.ui.server.AnalysisServerToolbarControlContribution">
             </control>
          </toolbar>
     </menuContribution>
     <menuContribution
           locationURI="popup:org.eclipse.ui.navigator.ProjectExplorer#PopupMenu?after=group.generate">
        <menu
              label="Dart">
           <visibleWhen>
+          <and>
+          <test
+                     property="com.google.dart.tools.debug.isInDartProject"
+                     value="true">
+               </test>
             <with variable="activeMenuSelection">
                <iterate>
                   <adapt
                         type="org.eclipse.core.resources.IResource">
                   </adapt>
-               </iterate>
+               </iterate>  
            </with>
+           </and>
         </visibleWhen>
           <command
                 commandId="com.google.dart.tools.ui.commands.unIgnoreResource"
                 label="Analyze"
                 style="push">
           </command>
           <command
                 commandId="com.google.dart.tools.ui.commands.ignoreResource"
                 label="Don&apos;t Analyze"
                 style="push">
@@ skipping 349 matching lines @@
             adaptable="true"
             class="com.google.dart.tools.ui.ProblemsLabelDecorator"
             id="com.google.dart.eclipse.ui.dart.decorator"
             label="Dart Problems Decorator"
             objectClass="org.eclipse.core.resources.IResource"
             state="true">
       </decorator>
    </extension>
 
 </plugin>