Clean up WebVR RequestPresent and make callback asynchronous.

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

 // Copyright 2016 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/VRDisplay.h"
 
 #include "core/dom/DOMException.h"
+#include "core/dom/DocumentUserGestureToken.h"
 #include "core/dom/FrameRequestCallback.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/ScriptedAnimationController.h"
 #include "core/frame/UseCounter.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "modules/vr/NavigatorVR.h"
 #include "modules/vr/VRController.h"
 #include "modules/vr/VRDisplayCapabilities.h"
 #include "modules/vr/VREyeParameters.h"
@@ skipping 310 matching lines @@
        m_layer.rightBounds().size() != 4)) {
     forceExitPresent();
     DOMException* exception = DOMException::create(
         InvalidStateError,
         "Layer bounds must either be an empty array or have 4 values");
     resolver->reject(exception);
     ReportPresentationResult(PresentationResult::InvalidLayerBounds);
     return promise;
   }
 
-  if (!m_capabilities->hasExternalDisplay()) {
-    // TODO: Need a proper VR compositor, but for the moment on mobile
-    // we'll just make the canvas fullscreen so that VrShell can pick it
-    // up through the standard (high latency) compositing path.
-    Fullscreen::requestFullscreen(*m_layer.source(),
-                                  Fullscreen::UnprefixedRequest);
-
-    // Check to see if the canvas is still the current fullscreen
-    // element once per second.
-    m_fullscreenCheckTimer.startRepeating(1.0, BLINK_FROM_HERE);
-  }
-
   if (firstPresent) {
     bool secureContext = scriptState->getExecutionContext()->isSecureContext();
     if (!m_display) {
       forceExitPresent();
       DOMException* exception = DOMException::create(
           InvalidStateError, "The service is no longer active.");
       resolver->reject(exception);
       return promise;
     }
     m_display->RequestPresent(
@@ skipping 42 matching lines @@
   m_display->ExitPresent();
 
   resolver->resolve();
 
   forceExitPresent();
 
   return promise;
 }
 
 void VRDisplay::beginPresent(ScriptPromiseResolver* resolver) {
+  Document* doc = m_navigatorVR->document();
+  std::unique_ptr<UserGestureIndicator> gestureIndicator;
   if (m_capabilities->hasExternalDisplay()) {
     forceExitPresent();
     DOMException* exception = DOMException::create(
         InvalidStateError,
         "VR Presentation not implemented for this VRDisplay.");
     resolver->reject(exception);
     ReportPresentationResult(
         PresentationResult::PresentationNotSupportedByDisplay);
     return;
+  } else {
+    // TODO: Need a proper VR compositor, but for the moment on mobile
+    // we'll just make the canvas fullscreen so that VrShell can pick it
+    // up through the standard (high latency) compositing path.
+    if (doc) {
+      // Since the callback for requestPresent is asynchronous, we've lost our
+      // UserGestureToken, and need to create a new one to enter fullscreen.
+      gestureIndicator =
+          wrapUnique(new UserGestureIndicator(DocumentUserGestureToken::create(
+              doc, UserGestureToken::Status::PossiblyExistingGesture)));
+    }
+    Fullscreen::requestFullscreen(*m_layer.source(),
+                                  Fullscreen::UnprefixedRequest);
+
+    // Check to see if the canvas is still the current fullscreen
+    // element once per second.
+    m_fullscreenCheckTimer.startRepeating(1.0, BLINK_FROM_HERE);
   }
 
-  Document* doc = m_navigatorVR->document();
   if (doc) {
     Platform::current()->recordRapporURL("VR.WebVR.PresentSuccess",
                                          WebURL(doc->url()));
   }
 
   m_isPresenting = true;
   ReportPresentationResult(PresentationResult::Success);
 
   updateLayerBounds();
 
@@ skipping 194 matching lines @@
   visitor->trace(m_capabilities);
   visitor->trace(m_stageParameters);
   visitor->trace(m_eyeParametersLeft);
   visitor->trace(m_eyeParametersRight);
   visitor->trace(m_layer);
   visitor->trace(m_renderingContext);
   visitor->trace(m_scriptedAnimationController);
 }
 
 }  // namespace blink