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 4f0875f6c3fa34008728d8e76ff9f30cdcd8a53c..00c97c9a021e0c9d7e80bd4d8870048b2ac093b6 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -287,12 +287,13 @@ 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) {
   GLThread* thread = static_cast<GLThread*>(gl_thread_.get());
   PostToGlThreadWhenReady(base::Bind(&VrShellGl::UpdateWebVRTextureBounds,
-                                     thread->GetVrShellGl(), left_bounds,
-                                     right_bounds));
+                                     thread->GetVrShellGl(), frame_index,
+                                     left_bounds, right_bounds));
 }
 
 // TODO(mthiesse): Do not expose GVR API outside of GL thread.
@@ -471,14 +472,10 @@ 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();
-
-  // Increment pose frame counter always, even if it's a faked pose.
-  pose->poseIndex = pose_index;
   pose->orientation.emplace(4);
 
   gfx::Transform inv_transform(