Revert of App button click exits WebVR presentation.

chrome/browser/android/vr_shell/ui_scene_manager.cc

Index: chrome/browser/android/vr_shell/ui_scene_manager.cc
diff --git a/chrome/browser/android/vr_shell/ui_scene_manager.cc b/chrome/browser/android/vr_shell/ui_scene_manager.cc
index e59a59a32d9bff92d16b95e437a593c2d6dca1e1..857d4d2eb59e1b0d48aa790947a17793b7cbfcfe 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager.cc
+++ b/chrome/browser/android/vr_shell/ui_scene_manager.cc
@@ -223,8 +223,11 @@
 }
 
 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(