Bug 1544170 Part 4 - Don't infinitely recurse in newChannelForURL on failure, r=loganfsmyth.

Differential Revision: https://phabricator.services.mozilla.com/D27411

--HG--
extra : rebase_source : 658df8227afa78826ef32b63f87e7c0f9554bda2

devtools/shared/DevToolsUtils.js

@@ -642,7 +642,7 @@ function mainThreadFetch(urlIn, aOptions = { loadFromCache: true,
  * @param {Object} options - The options object passed to @method fetch.
  * @return {nsIChannel} - The newly created channel. Throws on failure.
  */
-function newChannelForURL(url, { policy, window, principal }) {
+function newChannelForURL(url, { policy, window, principal }, recursing = false) {
   const securityFlags = Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL;
 
   let uri;
@@ -689,11 +689,17 @@ function newChannelForURL(url, { policy, window, principal }) {
   try {
     return NetUtil.newChannel(channelOptions);
   } catch (e) {
+    // Don't infinitely recurse if newChannel keeps throwing.
+    if (recursing) {
+      throw e;
+    }
+
     // In xpcshell tests on Windows, nsExternalProtocolHandler::NewChannel()
     // can throw NS_ERROR_UNKNOWN_PROTOCOL if the external protocol isn't
     // supported by Windows, so we also need to handle the exception here if
     // parsing the URL above doesn't throw.
-    return newChannelForURL("file://" + url, { policy, window, principal });
+    return newChannelForURL("file://" + url, { policy, window, principal },
+                            /* recursing */ true);
   }
 }