Properly pass postData into new tab

https://github.com/MoonchildProductions/moebius/pull/352

devtools/client/netmonitor/moz.build

@@ -17,6 +17,7 @@ DevToolsModules(
     'events.js',
     'filter-predicates.js',
     'l10n.js',
+    'open-request-in-tab.js',
     'panel.js',
     'performance-statistics-view.js',
     'prefs.js',

devtools/client/netmonitor/open-request-in-tab.js

@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/* eslint-disable mozilla/reject-some-requires */
+
+"use strict";
+
+let { Cc, Ci } = require("chrome");
+const Services = require("Services");
+const { gDevTools } = require("devtools/client/framework/devtools");
+
+/**
+ * Opens given request in a new tab.
+ */
+function openRequestInTab(request) {
+  let win = Services.wm.getMostRecentWindow(gDevTools.chromeWindowType);
+  let rawData = request.requestPostData ? request.requestPostData.postData : null;
+  let postData;
+
+  if (rawData && rawData.text) {
+    let stringStream = getInputStreamFromString(rawData.text);
+    postData = Cc["@mozilla.org/network/mime-input-stream;1"]
+      .createInstance(Ci.nsIMIMEInputStream);
+    postData.addHeader("Content-Type", "application/x-www-form-urlencoded");
+    postData.setData(stringStream);
+  }
+
+  win.gBrowser.selectedTab = win.gBrowser.addTab(request.url, null, null, postData);
+}
+
+function getInputStreamFromString(data) {
+  let stringStream = Cc["@mozilla.org/io/string-input-stream;1"]
+    .createInstance(Ci.nsIStringInputStream);
+  stringStream.data = data;
+  return stringStream;
+}
+
+module.exports = {
+  openRequestInTab,
+};

devtools/client/netmonitor/request-list-context-menu.js

@@ -10,6 +10,7 @@ const Services = require("Services");
 const { Task } = require("devtools/shared/task");
 const { Curl } = require("devtools/client/shared/curl");
 const { gDevTools } = require("devtools/client/framework/devtools");
+const { openRequestInTab } = require("devtools/client/netmonitor/open-request-in-tab");
 const Menu = require("devtools/client/framework/menu");
 const MenuItem = require("devtools/client/framework/menu-item");
 const { L10N } = require("./l10n");
@@ -186,8 +187,7 @@ RequestListContextMenu.prototype = {
    */
   openRequestInTab() {
     let win = Services.wm.getMostRecentWindow(gDevTools.chromeWindowType);
-    let { url } = this.selectedItem.attachment;
+    openRequestInTab(this.selectedItem.attachment);
-    win.openUILinkIn(url, "tab", { relatedToCurrent: true });
   },
 
   /**