Revert of App button click exits WebVR presentation.

chrome/browser/android/vr_shell/ui_scene_manager.cc

 // Copyright 2017 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 "chrome/browser/android/vr_shell/ui_scene_manager.h"
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/android/vr_shell/textures/ui_texture.h"
 #include "chrome/browser/android/vr_shell/ui_elements/permanent_security_warning.h"
 #include "chrome/browser/android/vr_shell/ui_elements/transient_security_warning.h"
@@ skipping 205 matching lines @@
 
   ConfigureSecurityWarnings();
 }
 
 void UiSceneManager::SetWebVrSecureOrigin(bool secure) {
   secure_origin_ = secure;
   ConfigureSecurityWarnings();
 }
 
 void UiSceneManager::OnAppButtonClicked() {
-  // App button click exits the WebVR presentation.
-  browser_->ExitPresent();
+  // Pressing the app button currenly pauses content rendering. Note: its still
+  // unclear what we want to do here and this will most likely change.
+  content_rendering_enabled_ = !content_rendering_enabled_;
+  scene_->SetWebVrRenderingEnabled(content_rendering_enabled_);
+  browser_->OnContentPaused(!content_rendering_enabled_);
 }
 
 void UiSceneManager::OnAppButtonGesturePerformed(
     UiInterface::Direction direction) {}
 
 void UiSceneManager::SetFullscreen(bool fullscreen) {
   // Make all VR scene UI elements visible if not in WebVR or fullscreen.
   for (UiElement* element : browser_ui_elements_) {
     element->set_visible(!fullscreen);
   }
@@ skipping 53 matching lines @@
 void UiSceneManager::SetLoadProgress(double progress) {}
 
 void UiSceneManager::SetHistoryButtonsEnabled(bool can_go_back,
                                               bool can_go_forward) {}
 
 int UiSceneManager::AllocateId() {
   return next_available_id_++;
 }
 
 }  // namespace vr_shell