Allow VRDisplay to specify which frame the layer bounds should be updated at.

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 4e89373e880abb856b4d4294b12cc7e518445574..5c8406909fe401e4b4bb3bc7574d9a3d49abea06 100644
--- a/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
+++ b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
@@ -53,7 +53,7 @@ void NonPresentingGvrDelegate::OnSwitchToPresentingDelegate() {
 void NonPresentingGvrDelegate::StopVSyncLoop() {
   vsync_task_.Cancel();
   if (!callback_.is_null())
-    callback_.Run(nullptr, 0);
+    callback_.Run(nullptr, 0, -1);
   callback_.Reset();
   if (binding_.is_bound())
     binding_.Close();
@@ -90,8 +90,7 @@ void NonPresentingGvrDelegate::OnVSync() {
 
   double time = (intervals * vsync_interval_).InSecondsF();
   if (!callback_.is_null()) {
-    callback_.Run(GetPose(), time);
-    callback_.Reset();
+    SendVSync(time, std::move(callback_));
   } else {
     pending_vsync_ = true;
     pending_time_ = time;
@@ -104,7 +103,7 @@ void NonPresentingGvrDelegate::GetVSync(const GetVSyncCallback& callback) {
     return;
   }
   pending_vsync_ = false;
-  callback.Run(GetPose(), pending_time_);
+  SendVSync(pending_time_, std::move(callback));
 }
 
 void NonPresentingGvrDelegate::UpdateVSyncInterval(long timebase_nanos,
@@ -115,17 +114,14 @@ void NonPresentingGvrDelegate::UpdateVSyncInterval(long timebase_nanos,
   StartVSyncLoop();
 }
 
-device::mojom::VRPosePtr NonPresentingGvrDelegate::GetPose() {
+void NonPresentingGvrDelegate::SendVSync(double time,
+                                         GetVSyncCallback callback) {
   gvr::ClockTimePoint target_time = gvr::GvrApi::GetTimePointNow();
   target_time.monotonic_system_time_nanos += kPredictionTimeWithoutVsyncNanos;
 
-  gvr::Mat4f head_mat =
-      gvr_api_->GetHeadSpaceFromStartSpaceRotation(target_time);
-  head_mat = gvr_api_->ApplyNeckModel(head_mat, 1.0f);
-
-  uint32_t pose_index = pose_index_++;
-
-  return VrShell::VRPosePtrFromGvrPose(head_mat, pose_index);
+  gvr::Mat4f head_mat = gvr_api_->ApplyNeckModel(
+      gvr_api_->GetHeadSpaceFromStartSpaceRotation(target_time), 1.0f);
+  callback.Run(VrShell::VRPosePtrFromGvrPose(head_mat), time, -1);
 }
 
 }  // namespace vr_shell