Issue 4580 - Replace ext.devtools with devtools

ext/common.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 143 matching lines @@
       return;
 
     let rawCatalog = JSON.parse(xhr.responseText);
     for (let msgId in rawCatalog)
     {
       if (!(msgId in catalog))
         catalog[msgId] = parseMessage(rawCatalog[msgId]);
     }
   };
 
+  /* Polyfills */

[Manish Jethani, 2017/10/11 22:46:00]

The code in this section will eventually move to polyfill.js

+
+  if (/\/devtools-panel\.html\b/.test(top.location.href))

[Manish Jethani, 2017/10/11 22:46:00]

chrome.devtools is not available outside the devtools panel

We have to make it available in background.js here though, I'll re-evaluate that
and maybe we do it differently.

+  {
+    chrome.devtools = {
+      panels: {
+        openResource() {}
+      },
+
+      inspectedWindow: {
+        reload() {}
+      },
+
+      onCreated: {
+        addListener(listener)
+        {
+          window.addEventListener("message", (event) =>
+          {
+            if (event.data.type == "devtools")
+              listener(new ext.Page(event.source));
+          });
+        }
+      }
+    };
+  }
+
   chrome.i18n = {
     getUILanguage()
     {
       return locales[0].replace(/_/g, "-");
     },
     getMessage(msgId, substitutions)
     {
       while (true)
       {
         let message = catalog[msgId];
@@ skipping 14 matching lines @@
         if (locales.length == 0)
           return "";
 
         let locale = locales.shift();
         readCatalog(locale, "common.json");
         readCatalog(locale, catalogFile);
       }
     }
   };
 }());