Implementation of elbow model for the controller position and rotation.

chrome/browser/android/vr_shell/vr_shell_gl.h

Index: chrome/browser/android/vr_shell/vr_shell_gl.h
diff --git a/chrome/browser/android/vr_shell/vr_shell_gl.h b/chrome/browser/android/vr_shell/vr_shell_gl.h
index 2bba8c2585c2fc47f578e37936783c3d0ddf0387..6a15b49e2219f8829fd75b6b89a461cd0eed45dc 100644
--- a/chrome/browser/android/vr_shell/vr_shell_gl.h
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.h
@@ -134,8 +134,8 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   void DrawWebVr();
   bool WebVrPoseByteIsValid(int pose_index_byte);
 
-  void UpdateController();
-  void HandleControllerInput(const gvr::Vec3f& forward_vector);
+  void UpdateController(const gvr::Vec3f& head_direction);
+  void HandleControllerInput(const gvr::Vec3f& head_direction);
   void HandleControllerAppButtonActivity(
       const gvr::Vec3f& controller_direction);
   void SendEventsToTarget(InputTarget input_target, int pixel_x, int pixel_y);
@@ -241,6 +241,8 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   // Attributes for gesture detection while holding app button.
   gvr::Vec3f controller_start_direction_;
 
+  gvr::Vec3f pointer_start_;
+
   base::WeakPtrFactory<VrShellGl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellGl);