Move deg<->rad conversions from cc to ui/gfx/geometry and use them more.

This also aims to eliminate _USE_MATH_DEFINES entirely by removing the last
vestiges of M_PI (at least, from the directories that can depend on ui/gfx).

Bug: none
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Iae16aa804aeb80a750af34b457d426b92dd6c302
Reviewed-on: https://chromium-review.googlesource.com/657905
Reviewed-by: Tim Volodine <timvolodine@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Rohit Rao (ping after 24h) <rohitrao@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Ian Vollick <vollick@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503069}

CrOS-Libchrome-Original-Commit: f9f3cebe6abf575ef8bda227a7dee4faa6cd312b

2 files changed, 32 insertions, 3 deletions

diff --git a/ui/gfx/geometry/angle_conversions.h b/ui/gfx/geometry/angle_conversions.h
new file mode 100644
index 0000000000..68e9209f72
--- /dev/null
+++ b/ui/gfx/geometry/angle_conversions.h
@@ -0,0 +1,29 @@
+// Copyright 2017 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 UI_GFX_GEOMETRY_ANGLE_CONVERSIONS_H_
+#define UI_GFX_GEOMETRY_ANGLE_CONVERSIONS_H_
+
+#include "base/numerics/math_constants.h"
+#include "ui/gfx/gfx_export.h"
+
+namespace gfx {
+
+GFX_EXPORT constexpr double DegToRad(double deg) {
+  return deg * base::kPiDouble / 180.0;
+}
+GFX_EXPORT constexpr float DegToRad(float deg) {
+  return deg * base::kPiFloat / 180.0f;
+}
+
+GFX_EXPORT constexpr double RadToDeg(double rad) {
+  return rad * 180.0 / base::kPiDouble;
+}
+GFX_EXPORT constexpr float RadToDeg(float rad) {
+  return rad * 180.0f / base::kPiFloat;
+}
+
+}  // namespace gfx
+
+#endif  // UI_GFX_GEOMETRY_ANGLE_CONVERSIONS_H_
diff --git a/ui/gfx/geometry/vector3d_f.cc b/ui/gfx/geometry/vector3d_f.cc
index c516172eba..749e330f27 100644
--- a/ui/gfx/geometry/vector3d_f.cc
+++ b/ui/gfx/geometry/vector3d_f.cc
@@ -7,9 +7,9 @@
 #include <cmath>
 
 #include "base/strings/stringprintf.h"
+#include "ui/gfx/geometry/angle_conversions.h"
 
 namespace {
-const float kRadiansToDegrees = 180.0f / 3.14159265f;
 const double kEpsilon = 1.0e-6;
 }
 
@@ -86,8 +86,8 @@ Vector3dF ScaleVector3d(const Vector3dF& v,
 
 float AngleBetweenVectorsInDegrees(const gfx::Vector3dF& base,
                                    const gfx::Vector3dF& other) {
-  return acos(gfx::DotProduct(base, other) / base.Length() / other.Length()) *
-         kRadiansToDegrees;
+  return gfx::RadToDeg(
+      std::acos(gfx::DotProduct(base, other) / base.Length() / other.Length()));
 }
 
 float ClockwiseAngleBetweenVectorsInDegrees(const gfx::Vector3dF& base,