Merge fx-team to m-c

browser/devtools/shadereditor/test/browser_se_bfcache.js

@@ -10,19 +10,18 @@ function ifWebGLSupported() {
   let { gFront, $, EVENTS, ShadersListView, ShadersEditorsView } = panel.panelWin;
 
   let reloaded = reload(target);
-  let firstProgram = yield once(gFront, "program-linked");
+  yield once(gFront, "program-linked");
   yield reloaded;
 
   let navigated = navigate(target, MULTIPLE_CONTEXTS_URL);
-  let [secondProgram, thirdProgram] = yield getPrograms(gFront, 2);
+  yield getPrograms(gFront, 2);
   yield navigated;
 
   let vsEditor = yield ShadersEditorsView._getEditor("vs");
   let fsEditor = yield ShadersEditorsView._getEditor("fs");
 
   yield navigateInHistory(target, "back", "will-navigate");
-  yield once(panel.panelWin, EVENTS.PROGRAMS_ADDED);
-  yield once(panel.panelWin, EVENTS.SOURCES_SHOWN);
+  yield waitForSources();
 
   is($("#content").hidden, false,
     "The tool's content should not be hidden.");
@@ -37,8 +36,7 @@ function ifWebGLSupported() {
     "The fragment shader editor contains the correct text.");
 
   yield navigateInHistory(target, "forward", "will-navigate");
-  yield once(panel.panelWin, EVENTS.PROGRAMS_ADDED);
-  yield once(panel.panelWin, EVENTS.SOURCES_SHOWN);
+  yield waitForSources();
 
   is($("#content").hidden, false,
     "The tool's content should not be hidden.");
@@ -54,4 +52,18 @@ function ifWebGLSupported() {
 
   yield teardown(panel);
   finish();
+
+  function waitForSources() {
+    let deferred = promise.defer();
+    let win = panel.panelWin;
+    // These events must fire in this in order and the second event fires
+    // synchronously after the first event, so we can't use Promise.all and the
+    // `once` helper.
+    win.once(win.EVENTS.PROGRAMS_ADDED, () => {
+      win.once(win.EVENTS.SOURCES_SHOWN, () => {
+        deferred.resolve();
+      });
+    });
+    return deferred.promise;
+  }
 }