Issue #3122 - Put base paths in the json viewer client deps.

The dependency modules are requested early. Seems CSP can block baseURL
on these networking requests, so add the base manually to the resource
paths to prevent network requests before the html base element is
resolved and active.

devtools/client/jsonview/converter-child.js

@@ -210,10 +210,10 @@ function initialHTML(doc) {
   let style = doc.createElement("link");
   style.rel = "stylesheet";
   style.type = "text/css";
-  style.href = "css/main.css";
+  style.href = base.href +"css/main.css";
 
   let script = doc.createElement("script");
-  script.src = "lib/require.js";
+  script.src = base.href + "lib/require.js";
   script.dataset.main = "viewer-config";
   script.defer = true;