Refactor VR math off of GVR types, onto gfx types where possible.

device/vr/vr_math.h

Index: device/vr/vr_math.h
diff --git a/device/vr/vr_math.h b/device/vr/vr_math.h
new file mode 100644
index 0000000000000000000000000000000000000000..72e21808f01ac1fc881f53986c97770e14a01877
--- /dev/null
+++ b/device/vr/vr_math.h
@@ -0,0 +1,58 @@
+// 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 DEVICE_VR_VR_MATH_H_
+#define DEVICE_VR_VR_MATH_H_
+
+#include "device/vr/vr_export.h"
+#include "device/vr/vr_types.h"
+
+namespace vr {
+
+void DEVICE_VR_EXPORT SetIdentityM(Mat4f* mat);
+void DEVICE_VR_EXPORT TranslateM(const Mat4f& mat,
+                                 const gfx::Vector3dF& translation,
+                                 Mat4f* out);
+void DEVICE_VR_EXPORT ScaleM(const Mat4f& mat,
+                             const gfx::Vector3dF& scale,
+                             Mat4f* out);
+
+gfx::Vector3dF DEVICE_VR_EXPORT MatrixVectorMul(const Mat4f& m,
+                                                const gfx::Vector3dF& v);
+gfx::Vector3dF DEVICE_VR_EXPORT MatrixVectorRotate(const Mat4f& m,
+                                                   const gfx::Vector3dF& v);
+void DEVICE_VR_EXPORT MatrixMul(const Mat4f& matrix1,
+                                const Mat4f& matrix2,
+                                Mat4f* out);
+void DEVICE_VR_EXPORT PerspectiveMatrixFromView(const gfx::RectF& fov,
+                                                float z_near,
+                                                float z_far,
+                                                Mat4f* out);
+
+// Provides the direction the head is looking towards as a 3x1 unit vector.
+gfx::Vector3dF DEVICE_VR_EXPORT GetForwardVector(const Mat4f& matrix);
+
+gfx::Vector3dF DEVICE_VR_EXPORT GetTranslation(const Mat4f& matrix);
+
+void DEVICE_VR_EXPORT QuatToMatrix(const Quatf& quat, Mat4f* out);
+
+// Normalize a vector, and return its original length.
+float DEVICE_VR_EXPORT NormalizeVector(gfx::Vector3dF* vec);
+
+void DEVICE_VR_EXPORT NormalizeQuat(Quatf* quat);
+
+Quatf DEVICE_VR_EXPORT QuatFromAxisAngle(const RotationAxisAngle& axis_angle);
+
+gfx::Point3F DEVICE_VR_EXPORT GetRayPoint(const gfx::Point3F& rayOrigin,
+                                          const gfx::Vector3dF& rayVector,
+                                          float scale);
+
+// Angle between the vectors' projections to the XZ plane.
+bool DEVICE_VR_EXPORT XZAngle(const gfx::Vector3dF& vec1,
+                              const gfx::Vector3dF& vec2,
+                              float* angle);
+
+}  // namespace vr
+
+#endif  // DEVICE_VR_VR_MATH_H_