Make various gfx classes more amenable to use as compile-time constants.

ui/gfx/geometry/quad_f.h

 // Copyright (c) 2012 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_QUAD_F_H_
 #define UI_GFX_GEOMETRY_QUAD_F_H_
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
 #include <iosfwd>
 #include <string>
 
 #include "base/logging.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/gfx_export.h"
 
 namespace gfx {
 
 // A Quad is defined by four corners, allowing it to have edges that are not
 // axis-aligned, unlike a Rect.
 class GFX_EXPORT QuadF {
  public:
-  QuadF() {}
-  QuadF(const PointF& p1, const PointF& p2, const PointF& p3, const PointF& p4)
+  constexpr QuadF() {}

[danakj, 2016/06/10 00:36:48]

nit: = default?

[Peter Kasting, 2016/06/10 05:50:06]

Fine with me, I have no preference.  Done in all three places.

+  constexpr QuadF(const PointF& p1,
+                  const PointF& p2,
+                  const PointF& p3,
+                  const PointF& p4)
       : p1_(p1),
         p2_(p2),
         p3_(p3),
         p4_(p4) {}
 
-  explicit QuadF(const RectF& rect)
+  constexpr explicit QuadF(const RectF& rect)
       : p1_(rect.x(), rect.y()),
         p2_(rect.right(), rect.y()),
         p3_(rect.right(), rect.bottom()),
         p4_(rect.x(), rect.bottom()) {}
 
   void operator=(const RectF& rect);
 
   void set_p1(const PointF& p) { p1_ = p; }
   void set_p2(const PointF& p) { p2_ = p; }
   void set_p3(const PointF& p) { p3_ = p; }
   void set_p4(const PointF& p) { p4_ = p; }
 
-  const PointF& p1() const { return p1_; }
-  const PointF& p2() const { return p2_; }
-  const PointF& p3() const { return p3_; }
-  const PointF& p4() const { return p4_; }
+  constexpr const PointF& p1() const { return p1_; }
+  constexpr const PointF& p2() const { return p2_; }
+  constexpr const PointF& p3() const { return p3_; }
+  constexpr const PointF& p4() const { return p4_; }
 
   // Returns true if the quad is an axis-aligned rectangle.
   bool IsRectilinear() const;
 
   // Returns true if the points of the quad are in counter-clockwise order. This
   // assumes that the quad is convex, and that no three points are collinear.
   bool IsCounterClockwise() const;
 
   // Returns true if the |point| is contained within the quad, or lies on on
   // edge of the quad. This assumes that the quad is convex.
@@ skipping 61 matching lines @@
 GFX_EXPORT QuadF operator-(const QuadF& lhs, const Vector2dF& rhs);
 
 // This is declared here for use in gtest-based unit tests but is defined in
 // the gfx_test_support target. Depend on that to use this in your unit test.
 // This should not be used in production code - call ToString() instead.
 void PrintTo(const QuadF& quad, ::std::ostream* os);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GEOMETRY_QUAD_F_H_