Pause drawing webvr when the App button is pressed

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 29434a3931c9b8d6cd332c116915be46fc4428a8..1483c88554e8d4b671d1982b7064ba3b7ae495ae 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager.cc
+++ b/chrome/browser/android/vr_shell/ui_scene_manager.cc
@@ -11,6 +11,9 @@
 #include "chrome/browser/android/vr_shell/ui_elements/transient_security_warning.h"
 #include "chrome/browser/android/vr_shell/ui_elements/ui_element.h"
 #include "chrome/browser/android/vr_shell/ui_scene.h"
+#include "chrome/browser/android/vr_shell/vr_gl_thread.h"
+#include "chrome/browser/android/vr_shell/vr_shell.h"
+#include "chrome/browser/android/vr_shell/vr_thread_envoy.h"
 
 namespace vr_shell {
 
@@ -32,8 +35,12 @@ static constexpr float kContentVerticalOffset = -0.26;
 
 }  // namespace
 
-UiSceneManager::UiSceneManager(UiScene* scene)
-    : scene_(scene), weak_ptr_factory_(this) {
+UiSceneManager::UiSceneManager(
+    const base::WeakPtr<VrThreadEnvoy>& weak_vr_thread_envoy,
+    UiScene* scene)
+    : weak_vr_thread_envoy_(weak_vr_thread_envoy),
+      scene_(scene),
+      weak_ptr_factory_(this) {
   std::unique_ptr<UiElement> element;
 
   // For now, use an ID range that does not conflict with the HTML UI.
@@ -100,6 +107,15 @@ void UiSceneManager::SetWebVRSecureOrigin(bool secure) {
   ConfigureSecurityWarnings();
 }
 
+void UiSceneManager::AppButtonPressed() {
+  // Pressing the app button currenly pauses content rendering. Note: its still
+  // unclear what we want to do here and this will most likely change.

[ymalik, 2017/04/28 00:12:04]

I'm just pausing the webvr rending for now. If y'all prefer just doing nothing
here until we figure out how we want to handle the app button, I'd be okay with
that too.

+  content_rendering_enabled_ = !content_rendering_enabled_;
+  scene_->SetWebVrRenderingEnabled(!content_rendering_enabled_);
+  weak_vr_thread_envoy_->PostTaskToMainThreadShell(&VrShell::OnContentPaused,
+                                                   content_rendering_enabled_);
+}
+
 void UiSceneManager::ConfigureSecurityWarnings() {
   bool enabled = web_vr_mode_ && !secure_origin_;
   permanent_security_warning_->visible = enabled;