Bug 995436 - Use different sponsored panel text for Release and non-Release [r=adw]

Package both text and hide the one that shouldn't be shown.

browser/base/content/newtab/newTab.js

@@ -19,6 +19,8 @@ XPCOMUtils.defineLazyModuleGetter(this, "Rect",
   "resource://gre/modules/Geometry.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "PrivateBrowsingUtils",
   "resource://gre/modules/PrivateBrowsingUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "UpdateChannel",
+  "resource://gre/modules/UpdateChannel.jsm");
 
 let {
   links: gLinks,

browser/base/content/newtab/newTab.xul

@@ -20,7 +20,8 @@
             title="&newtab.pageTitle;">
 
   <xul:panel id="sponsored-panel" orient="vertical" type="arrow">
-    <xul:description>&newtab.panel.message;</xul:description>
+    <xul:description id="sponsored-panel-release-descr">&newtab.sponsored.release.message;</xul:description>
+    <xul:description id="sponsored-panel-trial-descr">&newtab.sponsored.trial.message;</xul:description>
     <xul:label class="text-link"
                href="https://support.mozilla.org/kb/how-do-sponsored-tiles-work"
                value="&newtab.panel.link.text;" />

browser/base/content/newtab/page.js

@@ -28,6 +28,12 @@ let gPage = {
     this._sponsoredPanel = document.getElementById("sponsored-panel");
     let link = this._sponsoredPanel.querySelector(".text-link");
     link.addEventListener("click", () => this._sponsoredPanel.hidePopup());
+    if (UpdateChannel.get().startsWith("release")) {
+      document.getElementById("sponsored-panel-trial-descr").style.display = "none";
+    }
+    else {
+      document.getElementById("sponsored-panel-release-descr").style.display = "none";
+    }
 
     // Check if the new tab feature is enabled.
     let enabled = gAllPages.enabled;

browser/locales/en-US/chrome/browser/newTab.dtd

@@ -8,5 +8,6 @@
 <!ENTITY newtab.undo.undoButton "Undo.">
 <!ENTITY newtab.undo.restoreButton "Restore All.">
 <!ENTITY newtab.undo.closeTooltip "Hide">
-<!ENTITY newtab.panel.message "This site is being suggested because it has sponsored Mozilla, helping us promote openness, innovation and opportunity on the Web.">
+<!ENTITY newtab.sponsored.release.message "This Sponsor site was suggested because we hoped you’d find it interesting and because it supports Mozilla’s mission.">
+<!ENTITY newtab.sponsored.trial.message "This Trial Sponsor site was suggested because we hoped you’d find it interesting and because it supports Mozilla’s mission.">
 <!ENTITY newtab.panel.link.text "Learn more…">