Changeset 221016 in webkit

Timestamp:

Aug 22, 2017, 9:13:22 AM (9 years ago)

Author:

jer.noble@apple.com

Message:

Autoplay Muted Videos Don't Play When Outside Viewport
​https://bugs.webkit.org/show_bug.cgi?id=175748
<rdar://problem/33974383>

Reviewed by Eric Carlson.

Source/WebCore:

Test: media/video-restricted-invisible-autoplay-not-allowed-source.html

The media session is notified that its client (the media element) will begin autoplaying inside
prepareForLoad(), where the m_autoplaying flag is also set. But loading via <source> elements does not go
through prepareForLoad(); the HTML standard states that the <source> element loading path does not trigger the
"media element load algorithm" which is implemented in prepareForLoad(). Since the m_autoplaying flag is
initially set to true, notify the media session that the element will begin autoplaying inside the element's
constructor.

Drive-by fix: Doing the above causes other tests to crash, as purturbing play state during style change can cause
re-entrancy in the native controls code, or fail, since we will transition from autoplay -> play even if there's
not yet a src or source to the media element. Add a task queue for updating the autoplay state and check the ready
state before allowing autoplay to transition to play.

• html/HTMLMediaElement.cpp:

(WebCore::HTMLMediaElement::HTMLMediaElement):
(WebCore::HTMLMediaElement::~HTMLMediaElement):
(WebCore::HTMLMediaElement::canTransitionFromAutoplayToPlay const):
(WebCore::HTMLMediaElement::isVisibleInViewportChanged):

LayoutTests:

• media/video-restricted-invisible-autoplay-not-allowed-source-expected.txt: Added.
• media/video-restricted-invisible-autoplay-not-allowed-source.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/media/video-restricted-invisible-autoplay-not-allowed-source-expected.txt (added)
• LayoutTests/media/video-restricted-invisible-autoplay-not-allowed-source.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/html/HTMLMediaElement.cpp (modified) (4 diffs)
• Source/WebCore/html/HTMLMediaElement.h (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2017-08-22  Jer Noble  <jer.noble@apple.com>
+
+        Autoplay Muted Videos Don't Play When Outside Viewport
+        https://bugs.webkit.org/show_bug.cgi?id=175748
+        <rdar://problem/33974383>
+
+        Reviewed by Eric Carlson.
+
+        * media/video-restricted-invisible-autoplay-not-allowed-source-expected.txt: Added.
+        * media/video-restricted-invisible-autoplay-not-allowed-source.html: Added.
+
 2017-08-21  Matt Rajca  <mrajca@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2017-08-22  Jer Noble  <jer.noble@apple.com>
+
+        Autoplay Muted Videos Don't Play When Outside Viewport
+        https://bugs.webkit.org/show_bug.cgi?id=175748
+        <rdar://problem/33974383>
+
+        Reviewed by Eric Carlson.
+
+        Test: media/video-restricted-invisible-autoplay-not-allowed-source.html
+
+        The media session is notified that its client (the media element) will begin autoplaying inside
+        prepareForLoad(), where the m_autoplaying flag is also set. But loading via <source> elements does not go
+        through prepareForLoad(); the HTML standard states that the <source> element loading path does not trigger the
+        "media element load algorithm" which is implemented in prepareForLoad(). Since the m_autoplaying flag is
+        initially set to true, notify the media session that the element will begin autoplaying inside the element's
+        constructor.
+
+        Drive-by fix: Doing the above causes other tests to crash, as purturbing play state during style change can cause
+        re-entrancy in the native controls code, or fail, since we will transition from autoplay -> play even if there's
+        not yet a src or source to the media element. Add a task queue for updating the autoplay state and check the ready
+        state before allowing autoplay to transition to play.
+
+        * html/HTMLMediaElement.cpp:
+        (WebCore::HTMLMediaElement::HTMLMediaElement):
+        (WebCore::HTMLMediaElement::~HTMLMediaElement):
+        (WebCore::HTMLMediaElement::canTransitionFromAutoplayToPlay const):
+        (WebCore::HTMLMediaElement::isVisibleInViewportChanged):
+
 2017-08-21  Matt Rajca  <mrajca@apple.com>
 

trunk/Source/WebCore/html/HTMLMediaElement.cpp

@@ -520 +520 @@
     AudioSession::sharedSession().addMutedStateObserver(this);
 #endif
+
+    mediaSession().clientWillBeginAutoplaying();
 }
 
@@ -596 +598 @@
     m_playbackControlsManagerBehaviorRestrictionsQueue.close();
     m_resourceSelectionTaskQueue.close();
+    m_visibilityChangeTaskQueue.close();
 #if ENABLE(ENCRYPTED_MEDIA)
     m_encryptedMediaQueue.close();
@@ -2333 +2336 @@
 {
     if (isAutoplaying()
-     && mediaSession().autoplayPermitted()
-     && paused()
-     && autoplay()
-     && !pausedForUserInteraction()
-     && !document().isSandboxed(SandboxAutomaticFeatures))
+        && mediaSession().autoplayPermitted()
+        && paused()
+        && autoplay()
+        && !pausedForUserInteraction()
+        && !document().isSandboxed(SandboxAutomaticFeatures)
+        && m_readyState == HAVE_ENOUGH_DATA)
         return mediaSession().playbackPermitted(*this);
 
@@ -7622 +7626 @@
 void HTMLMediaElement::isVisibleInViewportChanged()
 {
-    updateShouldAutoplay();
-    scheduleUpdatePlaybackControlsManager();
+    m_visibilityChangeTaskQueue.enqueueTask([this] {
+        updateShouldAutoplay();
+        scheduleUpdatePlaybackControlsManager();
+    });
 }
 

trunk/Source/WebCore/html/HTMLMediaElement.h

@@ -902 +902 @@
     GenericTaskQueue<Timer> m_playbackControlsManagerBehaviorRestrictionsQueue;
     GenericTaskQueue<Timer> m_resourceSelectionTaskQueue;
+    GenericTaskQueue<Timer> m_visibilityChangeTaskQueue;
     RefPtr<TimeRanges> m_playedTimeRanges;
     GenericEventQueue m_asyncEventQueue;