Issue 154 - Added devtools panel showing blocked and blockable items

include.preload.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 134 matching lines @@
           // because we don't know how many rules are already in there
           stylesheet.addRule(selector, "display: none !important;");
         }
       }
     );
   });
 
   observer.observe(style.parentNode, {childList: true});
 }
 
+function traceHiddenElements(document, selectors)
+{
+  function check(element)
+  {
+    var matchedSelectors = [];
+
+    for (var i = 0; i < selectors.length; i++)
+    {
+      var selector = selectors[i];
+      var elements = document.querySelectorAll(selector);
+
+      for (var j = 0; j < elements.length; j++)
+      {
+        if (getComputedStyle(elements[j]).display == "none")
+        {
+          matchedSelectors.push(selector);
+          break;
+        }
+      }
+    }
+
+    if (matchedSelectors.length > 0)
+      ext.backgroundPage.sendMessage({type: "trace-elemhide", selectors: matchedSelectors});
+  }
+
+  function trace()
+  {
+    check();
+
+    var MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
+    if (MutationObserver)
+    {
+      new MutationObserver(check).observe(document,
+      {
+        childList: true,
+        attributes: true,
+        subtree: true
+      });
+    }
+  }
+
+  if (document.readyState == "loading")
+    document.addEventListener("DOMContentLoaded", trace);
+  else
+    trace();
+}
+
 function init(document)
 {
   // use Shadow DOM if available to don't mess with web pages that
   // rely on the order of their own <style> tags (#309). However we
   // must not create the shadow root in the response callback passed
   // to sendMessage(), otherwise Chrome breaks some websites (#450).
   var shadow = null;
   if ("createShadowRoot" in document.documentElement)
   {
     shadow = document.documentElement.createShadowRoot();
     shadow.appendChild(document.createElement("shadow"));
   }
 
   // Sets the currently used CSS rules for elemhide filters
-  var setElemhideCSSRules = function(selectors)
+  var setElemhideCSSRules = function(response)
   {
-    if (selectors.length == 0)
+    if (response.selectors.length == 0)
       return;
 
+    var selectors = response.selectors.slice(0);
     var style = document.createElement("style");
     style.setAttribute("type", "text/css");
 
     if (shadow)
     {
       shadow.appendChild(style);
 
       for (var i = 0; i < selectors.length; i++)
         selectors[i] = "::content " + selectors[i];
     }
@@ skipping 15 matching lines @@
         return;
       }
 
       // WebKit apparently chokes when the selector list in a CSS rule is huge.
       // So we split the elemhide selectors into groups.
       for (var i = 0; selectors.length > 0; i++)
       {
         var selector = selectors.splice(0, SELECTOR_GROUP_SIZE).join(", ");
         style.sheet.insertRule(selector + " { display: none !important; }", i);
       }
+
+      if (response.trace)
+        traceHiddenElements(document, response.selectors);
     };
 
     setRules();
     reinjectRulesWhenRemoved(document, style);
   };
 
   document.addEventListener("error", function(event)
   {
     checkCollapse(event.target);
   }, true);
@@ skipping 19 matching lines @@
   }, true);
 
   ext.backgroundPage.sendMessage({type: "get-selectors"}, setElemhideCSSRules);
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   init(document);
 }