browser(firefox): do not fail when decoding large responses (#2130)

String.fromCharCode cannot be used to convert very large arrays to strings. Use chunking in this case.

browser_patches/firefox/BUILD_NUMBER

@@ -1 +1 @@
-1090
+1091

browser_patches/firefox/patches/bootstrap.diff

@@ -1400,17 +1400,16 @@ index 0000000000000000000000000000000000000000..2b1fe7fa712ae210af3ebbccda084041
 +
 diff --git a/juggler/NetworkObserver.js b/juggler/NetworkObserver.js
 new file mode 100644
-index 0000000000000000000000000000000000000000..1a55b5498c18d2403eab21fe9149242f286157d4
+index 0000000000000000000000000000000000000000..4ed81876c3e176cf07fdeab4ca3fc83874f865a3
 --- /dev/null
 +++ b/juggler/NetworkObserver.js
-@@ -0,0 +1,794 @@
+@@ -0,0 +1,833 @@
 +"use strict";
 +
 +const {EventEmitter} = ChromeUtils.import('resource://gre/modules/EventEmitter.jsm');
 +const {Helper} = ChromeUtils.import('chrome://juggler/content/Helper.js');
 +const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
 +const {NetUtil} = ChromeUtils.import('resource://gre/modules/NetUtil.jsm');
-+const {CommonUtils} = ChromeUtils.import("resource://services-common/utils.js");
 +
 +
 +const Cc = Components.classes;
@@ -1978,7 +1977,7 @@ index 0000000000000000000000000000000000000000..1a55b5498c18d2403eab21fe9149242f
 +    let result = response.body;
 +    if (response.encodings && response.encodings.length) {
 +      for (const encoding of response.encodings)
-+        result = CommonUtils.convertString(result, encoding, 'uncompressed');
++        result = convertString(result, encoding, 'uncompressed');
 +    }
 +    return {base64body: btoa(result)};
 +  }
@@ -2171,6 +2170,46 @@ index 0000000000000000000000000000000000000000..1a55b5498c18d2403eab21fe9149242f
 +  }
 +}
 +
++function convertString(s, source, dest) {
++  const is = Cc["@mozilla.org/io/string-input-stream;1"].createInstance(
++    Ci.nsIStringInputStream
++  );
++  is.setData(s, s.length);
++  const listener = Cc["@mozilla.org/network/stream-loader;1"].createInstance(
++    Ci.nsIStreamLoader
++  );
++  let result = [];
++  listener.init({
++    onStreamComplete: function onStreamComplete(
++      loader,
++      context,
++      status,
++      length,
++      data
++    ) {
++      const array = Array.from(data);
++      const kChunk = 100000;
++      for (let i = 0; i < length; i += kChunk) {
++        const len = Math.min(kChunk, length - i);
++        const chunk = String.fromCharCode.apply(this, array.slice(i, i + len));
++        result.push(chunk);
++      }
++    },
++  });
++  const converter = Cc["@mozilla.org/streamConverters;1"].getService(
++    Ci.nsIStreamConverterService
++  ).asyncConvertData(
++    source,
++    dest,
++    listener,
++    null
++  );
++  converter.onStartRequest(null, null);
++  converter.onDataAvailable(null, is, 0, s.length);
++  converter.onStopRequest(null, null, null);
++  return result.join('');
++}
++
 +const errorMap = {
 +  'aborted': Cr.NS_ERROR_ABORT,
 +  'accessdenied': Cr.NS_ERROR_PORT_ACCESS_NOT_ALLOWED,