Encode frame number in pixel data for pose sync

chrome/browser/android/vr_shell/vr_shell.h

Index: chrome/browser/android/vr_shell/vr_shell.h
diff --git a/chrome/browser/android/vr_shell/vr_shell.h b/chrome/browser/android/vr_shell/vr_shell.h
index 2255ac87ffbc8226927ccaeb0e6e137a804532f3..42874c43de593640e1659f8c34f532f8ae244e97 100644
--- a/chrome/browser/android/vr_shell/vr_shell.h
+++ b/chrome/browser/android/vr_shell/vr_shell.h
@@ -73,6 +73,7 @@ class VrShell : public device::GvrDelegate {
   void UpdateWebVRTextureBounds(
       int eye, float left, float top, float width, float height) override;
   gvr::GvrApi* gvr_api() override;
+  void SetGvrPoseForWebVr(gvr::Mat4f pose, int32_t frameNumStarted) override;
 
   void ContentSurfaceChanged(
       JNIEnv* env,
@@ -157,6 +158,9 @@ class VrShell : public device::GvrDelegate {
   bool webvr_mode_ = false;
   bool webvr_secure_origin_ = false;
   int64_t webvr_warning_end_nanos_ = 0;
+  static constexpr int POSE_QUEUE_SIZE = 8;
+  gvr::Mat4f webvr_head_pose_[POSE_QUEUE_SIZE];
+  int32_t webvr_newest_pose_num_ = 0;
 
   base::WeakPtrFactory<VrShell> weak_ptr_factory_;