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

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 d13bcd4f1f79a0a55cea05e013eb33926e64bd15..0031fd451fe93dda0201ed24d97b1e8cd036a23a 100644
--- a/chrome/browser/android/vr_shell/vr_shell.h
+++ b/chrome/browser/android/vr_shell/vr_shell.h
@@ -121,8 +121,7 @@ class VrShell : public device::GvrDelegate, content::WebContentsObserver {
 
   void ForceExitVr();
 
-  static device::mojom::VRPosePtr VRPosePtrFromGvrPose(gvr::Mat4f head_mat,
-                                                       uint32_t pose_index);
+  static device::mojom::VRPosePtr VRPosePtrFromGvrPose(gvr::Mat4f head_mat);
 
  private:
   virtual ~VrShell();
@@ -138,7 +137,8 @@ class VrShell : public device::GvrDelegate, content::WebContentsObserver {
   // device::GvrDelegate implementation
   void SetWebVRSecureOrigin(bool secure_origin) override;
   void SubmitWebVRFrame() override;
-  void UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
+  void UpdateWebVRTextureBounds(int16_t frame_index,
+                                const gvr::Rectf& left_bounds,
                                 const gvr::Rectf& right_bounds) override;
   gvr::GvrApi* gvr_api() override;
   void SetWebVRRenderSurfaceSize(int width, int height) override;