We should pause silent WebAudio rendering in background tabs
https://bugs.webkit.org/show_bug.cgi?id=170299
<rdar://problem/31289132>
Reviewed by Eric Carlson.
Source/WebCore:
We should pause silent WebAudio rendering in background tabs since it uses CPU and is
not observable by the user. Such silent WebAudio rendering seems to be used by
doubleclick ads.
Test: webaudio/silent-audio-interrupted-in-background.html
* Modules/webaudio/AudioContext.cpp:
(WebCore::AudioContext::lazyInitialize):
(WebCore::AudioContext::uninitialize):
Have AudioContext register / unregister itself with the Document to get
visibility change notifications, similarly to what HTMLMediaElement was
already doing.
(WebCore::AudioContext::visibilityStateChanged):
Begin / End session interruption whenever the page visiblity changes.
* Modules/webaudio/AudioContext.h:
* WebCore.xcodeproj/project.pbxproj:
* dom/Document.cpp:
(WebCore::Document::registerForVisibilityStateChangedCallbacks):
(WebCore::Document::unregisterForVisibilityStateChangedCallbacks):
(WebCore::Document::visibilityStateChanged):
* dom/Document.h:
* dom/Element.h:
* dom/VisibilityChangeClient.h: Added.
(WebCore::VisibilityChangeClient::~VisibilityChangeClient):
* html/HTMLMediaElement.h:
Introduce a new VisibilityChangeClient interface and have both AudioContext
and HTMLMediaElement subclass it. Previously, the visibilityStateChanged()
function was on Element but this prevented AudioContext from registering
itself since AudioContext is not an Element.
LayoutTests:
Add layout test coverage.
* webaudio/silent-audio-interrupted-in-background-expected.txt: Added.
* webaudio/silent-audio-interrupted-in-background.html: Added.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@214721 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/LayoutTests/platform/ios/TestExpectations b/LayoutTests/platform/ios/TestExpectations
index 5db923a..1e7f603 100644
--- a/LayoutTests/platform/ios/TestExpectations
+++ b/LayoutTests/platform/ios/TestExpectations
@@ -311,6 +311,7 @@
webkit.org/b/165799 svg/animations/animations-paused-page-non-visible.html [ Skip ]
webkit.org/b/165799 svg/animations/animations-paused-in-background-page-iframe.html [ Skip ]
webkit.org/b/165799 svg/animations/animations-paused-in-background-page.html [ Skip ]
+webkit.org/b/165799 webaudio/silent-audio-interrupted-in-background.html [ Skip ]
# AutoFill button is not supported
fast/forms/auto-fill-button/mouse-down-input-mouse-release-auto-fill-button.html
