Notify VRDeviceProviders when there are pages listening for vrdisplayactivate

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

Index: third_party/WebKit/Source/modules/vr/NavigatorVR.cpp
diff --git a/third_party/WebKit/Source/modules/vr/NavigatorVR.cpp b/third_party/WebKit/Source/modules/vr/NavigatorVR.cpp
index a157e2c3d1b13e5066d01f441854b29eacde782c..de32e5af44b98de1a8a58c3e5f703478dd00bb36 100644
--- a/third_party/WebKit/Source/modules/vr/NavigatorVR.cpp
+++ b/third_party/WebKit/Source/modules/vr/NavigatorVR.cpp
@@ -94,7 +94,9 @@ DEFINE_TRACE(NavigatorVR) {
   DOMWindowProperty::trace(visitor);
 }
 
-NavigatorVR::NavigatorVR(LocalFrame* frame) : DOMWindowProperty(frame) {}
+NavigatorVR::NavigatorVR(LocalFrame* frame) : DOMWindowProperty(frame) {
+  frame->localDOMWindow()->registerEventListenerObserver(this);
+}
 
 NavigatorVR::~NavigatorVR() {}
 
@@ -117,4 +119,29 @@ void NavigatorVR::dispatchVRGestureEvent(VRDisplayEvent* event) {
   }
 }
 
+void NavigatorVR::didAddEventListener(LocalDOMWindow* window,
+                                      const AtomicString& eventType) {
+  if (eventType == EventTypeNames::vrdisplayactivate) {
+    controller()->setListeningForActivate(true);
+  } else if (eventType == EventTypeNames::vrdisplayconnect) {
+    // If the page is listening for connection events make sure we've created a
+    // controller so that we'll be notified of new devices.
+    controller();
+  }
+}
+
+void NavigatorVR::didRemoveEventListener(LocalDOMWindow* window,
+                                         const AtomicString& eventType) {
+  if (eventType == EventTypeNames::vrdisplayactivate &&
+      !window->hasEventListeners(EventTypeNames::vrdisplayactivate)) {
+    controller()->setListeningForActivate(false);
+  }
+}
+
+void NavigatorVR::didRemoveAllEventListeners(LocalDOMWindow* window) {
+  if (m_controller) {
+    m_controller->setListeningForActivate(false);
+  }
+}
+
 }  // namespace blink