title: How do I get permission to access my own extensions resources (a specific page)?
body: <p>Due to recent changes in the Chrome API, my plugin issues this error:</p>
  
  <blockquote>
    <p>Error during tabs.executeScript: Cannot access contents of url
    "chrome-extension://ecfgljdfndkhhbmhcnelbpnhkflgiokp/cm_signature_editor.html".
    Extension manifest must request permission to access this host.</p>
  </blockquote>
  
  <p>This never used to be the case. Now I wonder how I get the URL of the chrome extension into it's manifest file:</p>
  
  <p>I know I can get the url or a resource within my extension like so: </p>
  
  <p><code>chrome.extension.getURL('/manifest.json')</code></p>
  
  <p>But I don't know how that can work in the manifest file.</p>
  
  <p>Is there another way to get this code working?</p>
  
  <pre><code>chrome.tabs.executeScript(null, {code:function_to_execute}, function() {
      // callback
  });
  </code></pre>
  
  <p>What's interesting is that even when I hardcode the chrome URL it doesn't work (I get the same error)</p>
  
  <pre><code>"permissions" : [
      "tabs",
      "contextMenus",
      "chrome-extension://ecfgljdfndkhhbmhcnelbpnhkflgiokp/*"
    ],
  </code></pre>