VR: Fix dynamic resizing webVR page, revert FOV calculation changes.

device/vr/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 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_