Changeset 252178 in webkit

Timestamp:

Nov 7, 2019 12:06:07 AM (4 years ago)

Author:

svillar@igalia.com

Message:

VRDisplay should not prevent entering the back/forward cache
​https://bugs.webkit.org/show_bug.cgi?id=203105

Reviewed by Chris Dumez.

VRDisplay schedules asynchronous execution of events using the WindowEventLoop instead of
synchronously firing them. WindowEventLoop does correctly suspend while in cache.

Apart from that suspend()/resume() were implemented by forcing m_scriptedAnimationController
to suspend the VR request animation frame machinery while in cache.

Last but not least, stopPresenting() is now also called on suspension.

No new tests were added as there is no testing machinery for WebVR so far. It's unclear how
this unreleased feature will evolve as it's being replaced by WebXR.

• Modules/webvr/VRDisplay.cpp:

(WebCore::VRDisplay::dispatchVRDisplayEventInWindowEventLoop):
(WebCore::VRDisplay::platformDisplayConnected): Use dispatchVRDisplayEventInWindowEventLoop.
(WebCore::VRDisplay::platformDisplayDisconnected): Ditto.
(WebCore::VRDisplay::platformDisplayMounted): Ditto.
(WebCore::VRDisplay::platformDisplayUnmounted): Ditto.
(WebCore::VRDisplay::suspend): Added.
(WebCore::VRDisplay::resume): Added.
(WebCore::VRDisplay::stop): Call stopPresenting().
(WebCore::VRDisplay::shouldPreventEnteringBackForwardCache_DEPRECATED const): Deleted.

• Modules/webvr/VRDisplay.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• Modules/webvr/VRDisplay.cpp (modified) (3 diffs)
• Modules/webvr/VRDisplay.h (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-11-05  Sergio Villar Senin  <svillar@igalia.com>
+
+        VRDisplay should not prevent entering the back/forward cache
+        https://bugs.webkit.org/show_bug.cgi?id=203105
+
+        Reviewed by Chris Dumez.
+
+        VRDisplay schedules asynchronous execution of events using the WindowEventLoop instead of
+        synchronously firing them. WindowEventLoop does correctly suspend while in cache.
+
+        Apart from that suspend()/resume() were implemented by forcing m_scriptedAnimationController
+        to suspend the VR request animation frame machinery while in cache.
+
+        Last but not least, stopPresenting() is now also called on suspension.
+
+        No new tests were added as there is no testing machinery for WebVR so far. It's unclear how
+        this unreleased feature will evolve as it's being replaced by WebXR.
+
+        * Modules/webvr/VRDisplay.cpp:
+        (WebCore::VRDisplay::dispatchVRDisplayEventInWindowEventLoop):
+        (WebCore::VRDisplay::platformDisplayConnected): Use dispatchVRDisplayEventInWindowEventLoop.
+        (WebCore::VRDisplay::platformDisplayDisconnected): Ditto.
+        (WebCore::VRDisplay::platformDisplayMounted): Ditto.
+        (WebCore::VRDisplay::platformDisplayUnmounted): Ditto.
+        (WebCore::VRDisplay::suspend): Added.
+        (WebCore::VRDisplay::resume): Added.
+        (WebCore::VRDisplay::stop): Call stopPresenting().
+        (WebCore::VRDisplay::shouldPreventEnteringBackForwardCache_DEPRECATED const): Deleted.
+        * Modules/webvr/VRDisplay.h:
+
 2019-11-06  Devin Rousso  <drousso@apple.com>
 

trunk/Source/WebCore/Modules/webvr/VRDisplay.cpp

@@ -44 +44 @@
 #include "VRPose.h"
 #include "VRStageParameters.h"
+#include "WindowEventLoop.h"
 #include <wtf/IsoMallocInlines.h>
 
@@ -210 +211 @@
 }
 
+// Use a EventLoop instead of dispatching events synchronously because the
+// EventLoop correctly suspends when in the cache. This way VRDisplay does no
+// longer prevent caching in the back/forward cache.
+void VRDisplay::dispatchVRDisplayEventInEventLoop(const AtomString& eventName, Optional<VRDisplayEventReason>&& reason)
+{
+    auto event = VRDisplayEvent::create(eventName, makeRefPtr(this), WTFMove(reason));
+    queueTaskKeepingObjectAlive(*this, TaskSource::UserInteraction, [this, event = WTFMove(event)]() mutable {
+        if (!document())
+            return;
+        if (auto* window = document()->domWindow())
+            window->dispatchEvent(event);
+    });
+}
+
 void VRDisplay::platformDisplayConnected()
 {
-    document()->domWindow()->dispatchEvent(VRDisplayEvent::create(eventNames().vrdisplayconnectEvent, makeRefPtr(this), WTF::nullopt));
+    dispatchVRDisplayEventInEventLoop(eventNames().vrdisplayconnectEvent, WTF::nullopt);
 }
 
 void VRDisplay::platformDisplayDisconnected()
 {
-    document()->domWindow()->dispatchEvent(VRDisplayEvent::create(eventNames().vrdisplaydisconnectEvent, makeRefPtr(this), WTF::nullopt));
+    dispatchVRDisplayEventInEventLoop(eventNames().vrdisplaydisconnectEvent, WTF::nullopt);
 }
 
 void VRDisplay::platformDisplayMounted()
 {
-    document()->domWindow()->dispatchEvent(VRDisplayEvent::create(eventNames().vrdisplayactivateEvent, makeRefPtr(this), VRDisplayEventReason::Mounted));
+    dispatchVRDisplayEventInEventLoop(eventNames().vrdisplayactivateEvent, VRDisplayEventReason::Mounted);
 }
 
 void VRDisplay::platformDisplayUnmounted()
 {
-    document()->domWindow()->dispatchEvent(VRDisplayEvent::create(eventNames().vrdisplaydeactivateEvent, makeRefPtr(this), VRDisplayEventReason::Unmounted));
+    dispatchVRDisplayEventInEventLoop(eventNames().vrdisplaydeactivateEvent, VRDisplayEventReason::Unmounted);
 }
 
@@ -240 +255 @@
 }
 
-// FIXME: This should never prevent entering the back/forward cache.
-bool VRDisplay::shouldPreventEnteringBackForwardCache_DEPRECATED() const
-{
-    return true;
+void VRDisplay::suspend(ReasonForSuspension reason)
+{
+    if (m_scriptedAnimationController)
+        m_scriptedAnimationController->suspend();
+    if (reason == ReasonForSuspension::BackForwardCache)
+        stopPresenting();
+}
+
+void VRDisplay::resume()
+{
+    if (m_scriptedAnimationController)
+        m_scriptedAnimationController->resume();
 }
 
 void VRDisplay::stop()
 {
+    m_scriptedAnimationController = nullptr;
+    stopPresenting();
 }
 

trunk/Source/WebCore/Modules/webvr/VRDisplay.h

@@ -28 +28 @@
 #include "ActiveDOMObject.h"
 #include "EventTarget.h"
+#include "VRDisplayEventReason.h"
 #include "VREye.h"
 #include "VRLayerInit.h"
 #include "VRPlatformDisplayClient.h"
+#include <wtf/Optional.h>
 #include <wtf/RefCounted.h>
 
@@ -107 +109 @@
     // ActiveDOMObject
     const char* activeDOMObjectName() const override;
-    bool shouldPreventEnteringBackForwardCache_DEPRECATED() const override;
+    void suspend(ReasonForSuspension) override;
+    void resume() override;
     void stop() override;
 
@@ -113 +116 @@
 
     Document* document() { return downcast<Document>(scriptExecutionContext()); }
+
+    void dispatchVRDisplayEventInEventLoop(const AtomString& eventName, Optional<VRDisplayEventReason>&&);
 
     WeakPtr<VRPlatformDisplay> m_display;