bug 1606612: remote: pretty-print WebSocket JSON payloads when verbose logging r=remote-protocol-reviewers,whimboo

When remote.log.level is Log.Level.Info or above, verbose logging
is enabled and we pretty-print JSON payloads in requests to the
HTTPD in JSONHandler.

This patch matches the behaviour of the JSONHandler logging, where
JSON payloads are logged to stdout with special formatting before
being transmitted across WebSocket connections.

Differential Revision: https://phabricator.services.mozilla.com/D58506

--HG--
extra : moz-landing-system : lando

remote/Connection.jsm

@@ -6,11 +6,11 @@
 
 var EXPORTED_SYMBOLS = ["Connection"];
 
-const { Log } = ChromeUtils.import("chrome://remote/content/Log.jsm");
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
+const { Log } = ChromeUtils.import("chrome://remote/content/Log.jsm");
 const { UnknownMethodError } = ChromeUtils.import(
   "chrome://remote/content/Error.jsm"
 );
@@ -61,9 +61,10 @@ class Connection {
     this.sessions.set(session.id, session);
   }
 
-  send(message) {
-    log.trace(`<-(connection ${this.id}) ${JSON.stringify(message)}`);
-    this.transport.send(message);
+  send(body) {
+    const payload = JSON.stringify(body, null, Log.verbose ? "\t" : null);
+    log.trace(`<-(connection ${this.id}) ${payload}`);
+    this.transport.send(JSON.parse(payload));
   }
 
   /**