Revert of WebVR compositor bypass via BrowserMain context + mailbox

chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc

Index: chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
diff --git a/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
index c28141e3b75d596dc145a40358972e52e14cc75b..c25da54458e04fc8f1922be5bb5c9247182402dd 100644
--- a/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
+++ b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
@@ -20,11 +20,7 @@
     : task_runner_(base::ThreadTaskRunnerHandle::Get()),
       binding_(this),
       weak_ptr_factory_(this) {
-  // Context may be null, see VrShellDelegate#createNonPresentingNativeContext
-  // for possible reasons a context could fail to be created. For example,
-  // the user might uninstall apps or clear data after VR support was detected.
-  if (context)
-    gvr_api_ = gvr::GvrApi::WrapNonOwned(context);
+  gvr_api_ = gvr::GvrApi::WrapNonOwned(context);
 }
 
 NonPresentingGvrDelegate::~NonPresentingGvrDelegate() {
@@ -44,8 +40,7 @@
 void NonPresentingGvrDelegate::Pause() {
   vsync_task_.Cancel();
   vsync_paused_ = true;
-  if (gvr_api_)
-    gvr_api_->PauseTracking();
+  gvr_api_->PauseTracking();
 }
 
 void NonPresentingGvrDelegate::Resume() {
@@ -65,14 +60,12 @@
 
 void NonPresentingGvrDelegate::StopVSyncLoop() {
   vsync_task_.Cancel();
-  binding_.Close();
   if (!callback_.is_null()) {
     base::ResetAndReturn(&callback_)
         .Run(nullptr, base::TimeDelta(), -1,
-             device::mojom::VRVSyncProvider::Status::CLOSING);
+             device::mojom::VRVSyncProvider::Status::RETRY);
   }
-  if (gvr_api_)
-    gvr_api_->PauseTracking();
+  gvr_api_->PauseTracking();
   // If the loop is stopped, it's not considered to be paused.
   vsync_paused_ = false;
 }
@@ -80,10 +73,8 @@
 void NonPresentingGvrDelegate::StartVSyncLoop() {
   vsync_task_.Reset(
       base::Bind(&NonPresentingGvrDelegate::OnVSync, base::Unretained(this)));
-  if (gvr_api_) {
-    gvr_api_->RefreshViewerProfile();
-    gvr_api_->ResumeTracking();
-  }
+  gvr_api_->RefreshViewerProfile();
+  gvr_api_->ResumeTracking();
   OnVSync();
 }
 
@@ -145,12 +136,6 @@
   gvr::ClockTimePoint target_time = gvr::GvrApi::GetTimePointNow();
   target_time.monotonic_system_time_nanos += kPredictionTimeWithoutVsyncNanos;
 
-  if (!gvr_api_) {
-    callback.Run(device::mojom::VRPosePtr(nullptr), time, -1,
-                 device::mojom::VRVSyncProvider::Status::SUCCESS);
-    return;
-  }
-
   gvr::Mat4f head_mat = gvr_api_->ApplyNeckModel(
       gvr_api_->GetHeadSpaceFromStartSpaceRotation(target_time), 1.0f);
   callback.Run(VrShell::VRPosePtrFromGvrPose(head_mat), time, -1,
@@ -171,11 +156,6 @@
 void NonPresentingGvrDelegate::CreateVRDisplayInfo(
     const base::Callback<void(device::mojom::VRDisplayInfoPtr)>& callback,
     uint32_t device_id) {
-  if (!gvr_api_) {
-    callback.Run(device::mojom::VRDisplayInfoPtr(nullptr));
-    return;
-  }
-
   callback.Run(VrShell::CreateVRDisplayInfo(
       gvr_api_.get(), device::kInvalidRenderTargetSize, device_id));
 }