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

chrome/browser/android/vr_shell/vr_shell.cc

Index: chrome/browser/android/vr_shell/vr_shell.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell.cc b/chrome/browser/android/vr_shell/vr_shell.cc
index a02ab7150b4021407ccc3236507b6e8315fc8ad9..56a91e0115c92c8b85c91580b724406e1d8bd625 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -232,11 +232,12 @@ void VrShell::SetWebVRSecureOrigin(bool secure_origin) {
 
 void VrShell::SubmitWebVRFrame() {}
 
-void VrShell::UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
+void VrShell::UpdateWebVRTextureBounds(int16_t frame_index,
+                                       const gvr::Rectf& left_bounds,
                                        const gvr::Rectf& right_bounds) {
   PostToGlThreadWhenReady(base::Bind(&VrShellGl::UpdateWebVRTextureBounds,
-                                     gl_thread_->GetVrShellGl(), left_bounds,
-                                     right_bounds));
+                                     gl_thread_->GetVrShellGl(), frame_index,
+                                     left_bounds, right_bounds));
 }
 
 // TODO(mthiesse): Do not expose GVR API outside of GL thread.
@@ -410,13 +411,10 @@ void VrShell::SetUiCssSize(float width, float height, float dpr) {
   Java_VrShellImpl_setUiCssSize(env, j_vr_shell_.obj(), width, height, dpr);
 }
 
-device::mojom::VRPosePtr VrShell::VRPosePtrFromGvrPose(gvr::Mat4f head_mat,
-                                                       uint32_t pose_index) {
+device::mojom::VRPosePtr VrShell::VRPosePtrFromGvrPose(gvr::Mat4f head_mat) {
   device::mojom::VRPosePtr pose = device::mojom::VRPose::New();
 
   pose->timestamp = base::Time::Now().ToJsTime();
-
-  pose->poseIndex = pose_index;
   pose->orientation.emplace(4);
 
   gfx::Transform inv_transform(