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

ui/gfx/geometry/size.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_SIZE_H_
 #define UI_GFX_GEOMETRY_SIZE_H_
 
 #include <iosfwd>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/numerics/safe_math.h"
 #include "build/build_config.h"
 #include "ui/gfx/gfx_export.h"
 
 #if defined(OS_WIN)
 typedef struct tagSIZE SIZE;
 #elif defined(OS_MACOSX)
 typedef struct CGSize CGSize;
 #endif
 
 namespace gfx {
 
 // A size has width and height values.
 class GFX_EXPORT Size {
  public:
-  Size() : width_(0), height_(0) {}
-  Size(int width, int height)
+  constexpr Size() : width_(0), height_(0) {}
+  constexpr Size(int width, int height)
       : width_(width < 0 ? 0 : width), height_(height < 0 ? 0 : height) {}
 #if defined(OS_MACOSX)
   explicit Size(const CGSize& s);
 #endif
 
-  ~Size() {}
-
 #if defined(OS_MACOSX)
   Size& operator=(const CGSize& s);
 #endif
 
 #if defined(OS_WIN)
   SIZE ToSIZE() const;
 #elif defined(OS_MACOSX)
   CGSize ToCGSize() const;
 #endif
 
-  int width() const { return width_; }
-  int height() const { return height_; }
+  constexpr int width() const { return width_; }
+  constexpr int height() const { return height_; }
 
   void set_width(int width) { width_ = width < 0 ? 0 : width; }
   void set_height(int height) { height_ = height < 0 ? 0 : height; }
 
   // This call will CHECK if the area of this size would overflow int.
   int GetArea() const;
   // Returns a checked numeric representation of the area.
   base::CheckedNumeric<int> GetCheckedArea() const;
 
   void SetSize(int width, int height) {
@@ skipping 38 matching lines @@
                                    float y_scale);
 GFX_EXPORT Size ScaleToFlooredSize(const Size& size, float x_scale);
 GFX_EXPORT Size ScaleToRoundedSize(const Size& size,
                                    float x_scale,
                                    float y_scale);
 GFX_EXPORT Size ScaleToRoundedSize(const Size& size, float x_scale);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GEOMETRY_SIZE_H_