Notify VRDeviceProviders when there are pages listening for vrdisplayactivate

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/vr/NavigatorVR.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/DocumentUserGestureToken.h"
@@ skipping 76 matching lines @@
   return frame() ? frame()->document() : 0;
 }
 
 DEFINE_TRACE(NavigatorVR) {
   visitor->trace(m_controller);
 
   Supplement<Navigator>::trace(visitor);
   DOMWindowProperty::trace(visitor);
 }
 
-NavigatorVR::NavigatorVR(LocalFrame* frame) : DOMWindowProperty(frame) {}
+NavigatorVR::NavigatorVR(LocalFrame* frame) : DOMWindowProperty(frame) {
+  frame->localDOMWindow()->registerEventListenerObserver(this);
+}
 
 NavigatorVR::~NavigatorVR() {}
 
 const char* NavigatorVR::supplementName() {
   return "NavigatorVR";
 }
 
 void NavigatorVR::enqueueVREvent(VRDisplayEvent* event) {
   if (frame() && frame()->localDOMWindow()) {
     frame()->localDOMWindow()->enqueueWindowEvent(event);
   }
 }
 
 void NavigatorVR::dispatchVRGestureEvent(VRDisplayEvent* event) {
   if (frame() && frame()->localDOMWindow()) {
     UserGestureIndicator gestureIndicator(
         DocumentUserGestureToken::create(frame()->document()));
     event->setTarget(frame()->localDOMWindow());
     frame()->localDOMWindow()->dispatchEvent(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