Bug 1270983 - Wait for media to being playing before pause check to avoid timeout. r=jaws

MozReview-Commit-ID: 7F18fUU8asl

--HG--
extra : rebase_source : b0495ac5c936009f86f919e14efe71257eb8bf59

browser/base/content/test/general/browser_contextmenu.js

@@ -59,6 +59,7 @@ add_task(function* test_setup_html() {
     let videoIframe = doc.querySelector("#test-video-in-iframe");
     let video = videoIframe.contentDocument.querySelector("video");
     let awaitPause = ContentTaskUtils.waitForEvent(video, "pause");
+    yield ContentTaskUtils.waitForCondition(() => !video.paused, "Making sure video is playing before calling pause");
     video.pause();
     yield awaitPause;
 
@@ -66,6 +67,7 @@ add_task(function* test_setup_html() {
     // media documents always use a <video> tag.
     let audio = audioIframe.contentDocument.querySelector("video");
     awaitPause = ContentTaskUtils.waitForEvent(audio, "pause");
+    yield ContentTaskUtils.waitForCondition(() => !audio.paused, "Making sure audio is playing before calling pause");
     audio.pause();
     yield awaitPause;
   });