Bug 729011 - Make fullscr-toggler not affect viewport size. r=dao

Differential Revision: https://phabricator.services.mozilla.com/D97736

browser/base/content/browser-fullScreenAndPointerLock.js

@@ -790,15 +790,6 @@ var FullScreen = {
       !BrowserHandler.kiosk
     ) {
       gNavToolbox.setAttribute("fullscreenShouldAnimate", true);
-      // Hide the fullscreen toggler until the transition ends.
-      let listener = () => {
-        gNavToolbox.removeEventListener("transitionend", listener, true);
-        if (this._isChromeCollapsed) {
-          this._fullScrToggler.hidden = false;
-        }
-      };
-      gNavToolbox.addEventListener("transitionend", listener, true);
-      this._fullScrToggler.hidden = true;
     }
 
     gNavToolbox.style.marginTop =

browser/base/content/browser.css

@@ -876,8 +876,12 @@ menupopup[emptyplacesresult="true"] > .hide-if-empty-places-result {
 /*  Full Screen UI */
 
 #fullscr-toggler {
+  top: 0;
+  left: 0;
+  right: 0;
   height: 1px;
-  background: black;
+  position: fixed;
+  z-index: 2147483647;
 }
 
 #fullscreen-and-pointerlock-wrapper {

browser/base/content/browser.xhtml

@@ -2258,8 +2258,6 @@
   </toolbox>
   </box>
 
-  <hbox id="fullscr-toggler" hidden="true"/>
-
   <hbox flex="1" id="browser">
     <vbox id="browser-border-start" hidden="true" layer="true"/>
     <vbox id="sidebar-box" hidden="true" class="chromeclass-extrachrome">
@@ -2331,5 +2329,8 @@
   </vbox>
 
   <html:div id="a11y-announcement" role="alert"/>
+
+  <!-- Put it at the very end to make sure it's not covered by anything. -->
+  <html:div id="fullscr-toggler" hidden="hidden"/>
 </html:body>
 </html>