Issue 2816 - Restore Preview functionality

chrome/content/actor.jsm

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 let EXPORTED_SYMBOLS = ["shutdown", "getNodeInfo", "togglePreview",
                         "forgetNode"];
 
 const Ci = Components.interfaces;
@@ skipping 15 matching lines @@
 };
 
 DebuggerServer.addTabActor(actor, name);
 
 let shutdown = (function()
 {
   let executed = false;
   return function()
   {
     if (!executed)
-      DebuggerServer.removeTabActor(actor);
-    executed = true;
+    {
+      executed = true;
+      try
+      {
+        DebuggerServer.removeTabActor(actor);
+      }
+      catch (e)
+      {
+        // The call above will throw in the content process despite succeeding,
+        // see https://bugzilla.mozilla.org/show_bug.cgi?id=1189780.
+        Cu.reportError(e);
+      }
+    }
   }
 })();
 
 function Actor(connection, tabActor)
 {
 }
 
 Actor.prototype = {
   requestTypes: {
     nodeinfo: function(request, connection)
@@ skipping 87 matching lines @@
       context.document.documentElement.appendChild(context.style);
     }
     context.style.textContent = stylesheetData;
   }
   else
   {
     try
     {
       if (context.style && context.style.parentNode)
         context.style.parentNode.removeChild(context.style);
+      context.style = null;
     }
     catch (e)
     {
-      // If the window was closed (reloaded) we end up with dead object
+      // If the window was closed (reloaded) we end up with a dead object
       // reference (https://bugzilla.mozilla.org/show_bug.cgi?id=695480). Just
-      // ignore this case, we don't need to do anything.

[Thomas Greiner, 2015/07/31 12:48:03]

If the context is no longer valid anyway, what about calling "forgetNode" to get
rid of the node here?

[Wladimir Palant, 2015/07/31 14:40:04]

Done.

+      // forget this node then.
+      forgetNode(nodeID);
     }
-    context.style = null;
   }
 }
 
 function forgetNode(nodeID)
 {
   nodes.delete(nodeID);
 }