Don't dispatch vrdisplayactivate event if the page that listens for it is invisible

third_party/WebKit/Source/modules/vr/NavigatorVR.h

Index: third_party/WebKit/Source/modules/vr/NavigatorVR.h
diff --git a/third_party/WebKit/Source/modules/vr/NavigatorVR.h b/third_party/WebKit/Source/modules/vr/NavigatorVR.h
index b023345f89a5c6f5aa27f291f595be79dcd9fb9a..a88a304a318fc06d683fcb880b648fba403ab537 100644
--- a/third_party/WebKit/Source/modules/vr/NavigatorVR.h
+++ b/third_party/WebKit/Source/modules/vr/NavigatorVR.h
@@ -8,6 +8,7 @@
 #include "bindings/core/v8/ScriptPromise.h"
 #include "core/frame/DOMWindowProperty.h"
 #include "core/frame/LocalDOMWindow.h"
+#include "core/page/PageVisibilityObserver.h"
 #include "modules/ModulesExport.h"
 #include "modules/vr/VRDisplay.h"
 #include "modules/vr/VRDisplayEvent.h"
@@ -26,6 +27,7 @@ class MODULES_EXPORT NavigatorVR final
     : public GarbageCollectedFinalized<NavigatorVR>,
       public Supplement<Navigator>,
       public DOMWindowProperty,
+      public PageVisibilityObserver,
       public LocalDOMWindow::EventListenerObserver {
   USING_GARBAGE_COLLECTED_MIXIN(NavigatorVR);
   WTF_MAKE_NONCOPYABLE(NavigatorVR);
@@ -47,6 +49,9 @@ class MODULES_EXPORT NavigatorVR final
   // Dispatches a user gesture event immediately.
   void dispatchVRGestureEvent(VRDisplayEvent*);
 
+  // Inherited from PageVisibilityObserver.
+  void pageVisibilityChanged() override;
+
   // Inherited from LocalDOMWindow::EventListenerObserver.
   void didAddEventListener(LocalDOMWindow*, const AtomicString&) override;
   void didRemoveEventListener(LocalDOMWindow*, const AtomicString&) override;
@@ -65,6 +70,9 @@ class MODULES_EXPORT NavigatorVR final
   void fireVRDisplayPresentChange(VRDisplay*);
 
   Member<VRController> m_controller;
+
+  // Whether this page is listening for vrdisplayactivate event.
+  bool m_listeningForActivate = false;
 };
 
 }  // namespace blink