Bug 993329 - Remove inline event handlers in newTab.xul [r=adw]

Add listener from page's init instead of inline.

--HG--
extra : rebase_source : 3a635d20bbb2b35caa23c4d7a5823172d066aee9

browser/base/content/newtab/newTab.xul

@@ -21,7 +21,6 @@
     <xul:description>&newtab.panel.message;</xul:description>
     <xul:label class="text-link"
                href="https://support.mozilla.org/kb/how-do-sponsored-tiles-work"
-               onclick="this.parentNode.hidePopup();"
                value="&newtab.panel.link.text;" />
   </xul:panel>
 

browser/base/content/newtab/page.js

@@ -25,6 +25,8 @@ let gPage = {
 
     // Initialize sponsored panel
     this._sponsoredPanel = document.getElementById("sponsored-panel");
+    let link = this._sponsoredPanel.querySelector(".text-link");
+    link.addEventListener("click", () => this._sponsoredPanel.hidePopup());
 
     // Check if the new tab feature is enabled.
     let enabled = gAllPages.enabled;