Support subpixel layout for borders.

third_party/WebKit/Source/core/style/BorderEdge.h

 // Copyright 2014 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 BorderEdge_h
 #define BorderEdge_h
 
 #include "core/style/ComputedStyleConstants.h"
 #include "platform/graphics/Color.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 struct BorderEdge {
   STACK_ALLOCATED();
 
  public:
-  BorderEdge(int edgeWidth,
+  BorderEdge(float edgeWidth,
              const Color& edgeColor,
              EBorderStyle edgeStyle,
              bool edgeIsPresent = true);
   BorderEdge();
 
   bool hasVisibleColorAndStyle() const;
   bool shouldRender() const;
   bool presentButInvisible() const;
   bool obscuresBackgroundEdge() const;
   bool obscuresBackground() const;
-  int usedWidth() const;
+  float usedWidth() const;
 
   bool sharesColorWith(const BorderEdge& other) const;
 
   EBorderStyle borderStyle() const { return static_cast<EBorderStyle>(style); }
 
   enum DoubleBorderStripe { DoubleBorderStripeOuter, DoubleBorderStripeInner };
 
-  int getDoubleBorderStripeWidth(DoubleBorderStripe) const;
+  float getDoubleBorderStripeWidth(DoubleBorderStripe) const;
 
-  int width;
+  float width() const { return m_width; }
+
   Color color;
   bool isPresent;
 
  private:
   unsigned style : 4;  // EBorderStyle
+  float m_width;
 };
 
 }  // namespace blink
 
 #endif  // BorderEdge_h