Implementation of elbow model for the controller position and rotation.

chrome/browser/android/vr_shell/vr_shell_renderer.h

Index: chrome/browser/android/vr_shell/vr_shell_renderer.h
diff --git a/chrome/browser/android/vr_shell/vr_shell_renderer.h b/chrome/browser/android/vr_shell/vr_shell_renderer.h
index 81811d3b458a5e3d2b96ec4eb93b3ff02c345437..2fb4b7262d069984b87b5d1768fe8e05e2b2774c 100644
--- a/chrome/browser/android/vr_shell/vr_shell_renderer.h
+++ b/chrome/browser/android/vr_shell/vr_shell_renderer.h
@@ -152,7 +152,7 @@ class LaserRenderer : public BaseQuadRenderer {
   LaserRenderer();
   ~LaserRenderer() override;
 
-  void Draw(const gvr::Mat4f& view_proj_matrix);
+  void Draw(float opacity, const gvr::Mat4f& view_proj_matrix);
 
  private:
   GLuint model_view_proj_matrix_handle_;
@@ -161,6 +161,7 @@ class LaserRenderer : public BaseQuadRenderer {
   GLuint color_handle_;
   GLuint fade_point_handle_;
   GLuint fade_end_handle_;
+  GLuint opacity_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(LaserRenderer);
 };
@@ -171,12 +172,15 @@ class ControllerRenderer : public BaseRenderer {
   ~ControllerRenderer() override;
 
   void SetUp(std::unique_ptr<VrControllerModel> model);
-  void Draw(VrControllerModel::State state, const gvr::Mat4f& view_proj_matrix);
+  void Draw(VrControllerModel::State state,
+            float opacity,
+            const gvr::Mat4f& view_proj_matrix);
   bool IsSetUp() const { return setup_; }
 
  private:
   GLuint model_view_proj_matrix_handle_;
   GLuint tex_uniform_handle_;
+  GLuint opacity_handle_;
   GLuint indices_buffer_ = 0;
   GLuint vertex_buffer_ = 0;
   GLint position_components_ = 0;