title: Addons Compatibility with Firefox 48
body: <p>I have an addon correctly working just up to FF 47.I know that with e10s FF 48, it has some compatibility troubles. Here a brief list of the lines of code I think they are affected by the new multiprocess model of the browser:</p>
  
  <pre><code>1.let { Cc, Ci } = require('chrome'); 
  
  2.const { Cu } = require("chrome");
  
  3.require("sdk/tabs").on("ready",logURL);
  
  4.Cu.import("resource://gre/modules/FileUtils.jsm"); 
  
  5.const {TextDecoder, TextEncoder, OS} = Cu.import("resource://gre/modules/osfile.jsm", {}); 
  
  6. file = FileUtils.getFile("Home", [".cp.txt"]); //reopen the file just saved 
  
  7. var txt = ""; 
  var fstream = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(Ci.nsIFileInputStream); 
  var cstream = Cc["@mozilla.org/intl/converter-input-stream;1"].createInstance(Ci.nsIConverterInputStream); 
  fstream.init(file, -1, 0, 0); cstream.init(fstream, "UTF-8", 0, 0); let str = {}; 
  let read = 0; 
  do { 
  read = cstream.readString(0xffffffff, str); // read as much as we can and put it in str.value 
  txt += str.value; 
  } while (read != 0); 
  cstream.close(); // this closes fstream // use 0x02 | 0x10 to open file for appending. // save the domain option in file 
  foStream.init(file, 0x02 | 0x08 | 0x20, 0666, 0); 
  converter.init(foStream, "UTF-8", 0, 0); 
  var sEP = txt + '\n' + 'h' + '\n'; // encrypt new path converter.writeString(sEP); converter.close(); // this closes foStream 
  console.log('saved h'); }
  </code></pre>
  
  <p>I need to know, first of all, if all these elements are effectively problematic  with new FF (I am pretty sure 6 and 7 are not compatible — the XUL and XPCOM are obsolete and work on the same thread —, but not so sure for the other lines), and finally if there are surrogate constructs for the 48 version in order to solve the same problems (input/output and so on). In particular, it is essential for the add-on the use of the tabs mechanism (for reading the URL of a tab). Thanks for the help. </p>