Remove unnecessary UI element math.

chrome/browser/android/vr_shell/vr_math.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_ANDROID_VR_SHELL_VR_MATH_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_VR_MATH_H_
 
 #include <array>
 
 #include "third_party/gvr-android-sdk/src/libraries/headers/vr/gvr/capi/include/gvr_types.h"
@@ skipping 24 matching lines @@
 } RotationAxisAngle;
 
 typedef struct Colorf {
   float r;
   float g;
   float b;
   float a;
 } Colorf;
 
 void SetIdentityM(gvr::Mat4f& mat);
-
 void TranslateM(gvr::Mat4f& tmat, gvr::Mat4f& mat, float x, float y, float z);
-void TranslateMRight(gvr::Mat4f& tmat,
-                     gvr::Mat4f& mat,
-                     float x,
-                     float y,
-                     float z);
-
 void ScaleM(gvr::Mat4f& tmat, const gvr::Mat4f& mat, float x, float y, float z);
-void ScaleMRight(gvr::Mat4f& tmat,
-                 const gvr::Mat4f& mat,
-                 float x,
-                 float y,
-                 float z);
 
 // Util functions that are copied from the treasure_hunt NDK demo in
 // third_party/gvr-andoir-sdk/ folder.
 gvr::Mat4f MatrixTranspose(const gvr::Mat4f& mat);
 std::array<float, 4> MatrixVectorMul(const gvr::Mat4f& matrix,
                                      const std::array<float, 4>& vec);
 std::array<float, 3> MatrixVectorMul(const gvr::Mat4f& matrix,
                                      const std::array<float, 3>& vec);
 gvr::Vec3f MatrixVectorMul(const gvr::Mat4f& m, const gvr::Vec3f& v);
 gvr::Vec3f MatrixVectorRotate(const gvr::Mat4f& m, const gvr::Vec3f& v);
 gvr::Mat4f MatrixMul(const gvr::Mat4f& matrix1, const gvr::Mat4f& matrix2);
 gvr::Mat4f PerspectiveMatrixFromView(const gvr::Rectf& fov,
                                      float z_near,
                                      float z_far);
 
 // Provides the direction the head is looking towards as a 3x1 unit vector.
 gvr::Vec3f GetForwardVector(const gvr::Mat4f& matrix);
 
 gvr::Vec3f GetTranslation(const gvr::Mat4f& matrix);
 
-gvr::Quatf QuatMultiply(const gvr::Quatf& a, const gvr::Quatf& b);
-
 gvr::Mat4f QuatToMatrix(const gvr::Quatf& quat);
 
 float VectorLength(const gvr::Vec3f& vec);
+gvr::Vec3f VectorSubtract(const gvr::Vec3f& a, const gvr::Vec3f& b);
+float VectorDot(const gvr::Vec3f& a, const gvr::Vec3f& b);
 
 // Normalize a vector, and return its original length.
 float NormalizeVector(gvr::Vec3f& vec);
 
-float VectorDot(const gvr::Vec3f& a, const gvr::Vec3f& b);
-
 void NormalizeQuat(gvr::Quatf& quat);
 
 gvr::Quatf QuatFromAxisAngle(const gvr::Vec3f& axis, float angle);
 
 gvr::Vec3f GetRayPoint(const gvr::Vec3f& rayOrigin,
                        const gvr::Vec3f& rayVector,
                        float scale);
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_MATH_H_