Bug 1511235 - part2 : add test. r=jya,baku

Add new webidl method for testing only and a test.

Differential Revision: https://phabricator.services.mozilla.com/D13805

--HG--
extra : moz-landing-system : lando

dom/html/HTMLMediaElement.cpp

@@ -1631,6 +1631,10 @@ void HTMLMediaElement::SetVisible(bool aVisible) {
   }
 }
 
+bool HTMLMediaElement::IsVideoDecodingSuspended() const {
+  return mDecoder && mDecoder->IsVideoDecodingSuspended();
+}
+
 already_AddRefed<layers::Image> HTMLMediaElement::GetCurrentImage() {
   MarkAsTainted();
 

dom/html/HTMLMediaElement.h

@@ -560,6 +560,9 @@ class HTMLMediaElement : public nsGenericHTMLElement,
   // For use by mochitests. Enabling pref "media.test.video-suspend"
   bool HasSuspendTaint() const;
 
+  // For use by mochitests.
+  bool IsVideoDecodingSuspended() const;
+
   // Synchronously, return the next video frame and mark the element unable to
   // participate in decode suspending.
   //

dom/media/MediaDecoder.cpp

@@ -434,9 +434,11 @@ void MediaDecoder::OnPlaybackEvent(MediaPlaybackEvent&& aEvent) {
       break;
     case MediaPlaybackEvent::EnterVideoSuspend:
       GetOwner()->DispatchAsyncEvent(NS_LITERAL_STRING("mozentervideosuspend"));
+      mIsVideoDecodingSuspended = true;
       break;
     case MediaPlaybackEvent::ExitVideoSuspend:
       GetOwner()->DispatchAsyncEvent(NS_LITERAL_STRING("mozexitvideosuspend"));
+      mIsVideoDecodingSuspended = false;
       break;
     case MediaPlaybackEvent::StartVideoSuspendTimer:
       GetOwner()->DispatchAsyncEvent(
@@ -459,6 +461,10 @@ void MediaDecoder::OnPlaybackEvent(MediaPlaybackEvent&& aEvent) {
   }
 }
 
+bool MediaDecoder::IsVideoDecodingSuspended() const {
+  return mIsVideoDecodingSuspended;
+}
+
 void MediaDecoder::OnPlaybackErrorEvent(const MediaResult& aError) {
   DecodeError(aError);
 }

dom/media/MediaDecoder.h

@@ -312,6 +312,8 @@ class MediaDecoder : public DecoderDoctorLifeLogger<MediaDecoder> {
 
   void SetIsBackgroundVideoDecodingAllowed(bool aAllowed);
 
+  bool IsVideoDecodingSuspended() const;
+
   /******
    * The following methods must only be called on the main
    * thread.
@@ -578,6 +580,9 @@ class MediaDecoder : public DecoderDoctorLifeLogger<MediaDecoder> {
   MediaEventListener mOnDecodeWarning;
   MediaEventListener mOnNextFrameStatus;
 
+  // True if we have suspended video decoding.
+  bool mIsVideoDecodingSuspended = false;
+
  protected:
   // PlaybackRate and pitch preservation status we should start at.
   double mPlaybackRate;

dom/webidl/HTMLMediaElement.webidl

@@ -204,13 +204,14 @@ partial interface HTMLMediaElement {
 };
 
 /*
- * This is an API for simulating visibility changes to help debug and write
+ * These APIs are testing only, they are used to simulate visibility changes to help debug and write
  * tests about suspend-video-decoding.
  *
  * - SetVisible() is for simulating visibility changes.
  * - HasSuspendTaint() is for querying that the element's decoder cannot suspend
  *   video decoding because it has been tainted by an operation, such as
  *   drawImage().
+ * - isVideoDecodingSuspended() is used to know whether video decoding has suspended.
  */
 partial interface HTMLMediaElement {
   [Pref="media.test.video-suspend"]
@@ -218,6 +219,9 @@ partial interface HTMLMediaElement {
 
   [Pref="media.test.video-suspend"]
   boolean hasSuspendTaint();
+
+  [ChromeOnly]
+  readonly attribute boolean isVideoDecodingSuspended;
 };
 
 /* Audio Output Devices API */

toolkit/content/tests/browser/browser.ini

@@ -103,6 +103,10 @@ uses-unsafe-cpows = true
 [browser_isSynthetic.js]
 [browser_keyevents_during_autoscrolling.js]
 [browser_label_textlink.js]
+[browser_suspend_videos_outside_viewport.js]
+support-files =
+  file_outside_viewport_videos.html
+  gizmo.mp4
 [browser_mediaPlayback.js]
 tags = audiochannel
 [browser_mediaPlayback_mute.js]

toolkit/content/tests/browser/browser_suspend_videos_outside_viewport.js

@@ -0,0 +1,33 @@
+/**
+ * This test is used to ensure we suspend video decoding if video is not in the
+ * viewport.
+ */
+"use strict";
+
+const PAGE = "https://example.com/browser/toolkit/content/tests/browser/file_outside_viewport_videos.html";
+
+async function test_suspend_video_decoding() {
+  let videos = content.document.getElementsByTagName("video");
+  for (let video of videos) {
+    info(`- start video on the ${video.id} side and outside the viewport -`);
+    await video.play();
+    ok(true, `video started playing`);
+    ok(video.isVideoDecodingSuspended, `video decoding is suspended`);
+  }
+}
+
+add_task(async function setup_test_preference() {
+  await SpecialPowers.pushPrefEnv({"set": [
+    ["media.suspend-bkgnd-video.enabled", true],
+    ["media.suspend-bkgnd-video.delay-ms", 0],
+  ]});
+});
+
+add_task(async function start_test() {
+  await BrowserTestUtils.withNewTab({
+    gBrowser,
+    url: PAGE,
+  }, async browser => {
+    await ContentTask.spawn(browser, null, test_suspend_video_decoding);
+  });
+});

toolkit/content/tests/browser/file_outside_viewport_videos.html

@@ -0,0 +1,41 @@
+<html>
+<head>
+  <title>outside viewport videos</title>
+<style>
+/**
+ * These CSS would move elements to the far left/right/top/bottom where user
+ * can not see elements in the viewport if user doesn't scroll the page.
+ */
+.outside-left {
+  position: absolute;
+  left: -1000%;
+}
+.outside-right {
+  position: absolute;
+  right: -1000%;
+}
+.outside-top {
+  position: absolute;
+  top: -1000%;
+}
+.outside-bottom {
+  position: absolute;
+  bottom: -1000%;
+}
+</style>
+</head>
+<body>
+	<div class="outside-left">
+		<video id="left" src="gizmo.mp4">
+	</div>
+	<div class="outside-right">
+		<video id="right" src="gizmo.mp4">
+	</div>
+	<div class="outside-top">
+		<video id="top" src="gizmo.mp4">
+	</div>
+	<div class="outside-bottom">
+		<video id="bottom" src="gizmo.mp4">
+	</div>
+</body>
+</html>