title: Chrome Extension: sendRequest to content script inside inner iframes?
body: <p>I have injected a content script file to all pages and inner iframes using <code>"all_frames": true</code> but when I send a request from popup only top window is receiving it. Any idea how can send it to all inner frames or at least last focused window/document?</p>
  
  <pre><code>Popup.html (page action):
  ===========
  chrome.tabs.getSelected(null, function(tab) {
      chrome.tabs.sendRequest(tab.id, {...}, function(response) {...});
  });
  
  content_script.js
  =================
  chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
      sendResponse({...});
  });
  </code></pre>
  
  <p>I have checked that content script is working in inner frames.</p>
  
  <p>I'm trying to retrieve text selection which may be in inner frames.</p>
  
  <p>(By the way I prefer not to open connection by every and all content script, that's a big overhead.)</p>