Make the FloatSize constructor from an IntSize explicit.

third_party/WebKit/Source/platform/geometry/FloatSize.h

 /*
  * Copyright (C) 2003, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2005 Nokia.  All rights reserved.
  *               2008 Eric Seidel <eric@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 32 matching lines @@
 
 namespace blink {
 
 class IntSize;
 class LayoutSize;
 
 class PLATFORM_EXPORT FloatSize {
 public:
     FloatSize() : m_width(0), m_height(0) { }
     FloatSize(float width, float height) : m_width(width), m_height(height) { }
-    FloatSize(const IntSize& size) : m_width(size.width()), m_height(size.height()) { }
+    explicit FloatSize(const IntSize& size) : m_width(size.width()), m_height(size.height()) { }
     FloatSize(const SkSize& size) : m_width(size.width()), m_height(size.height()) { }
     explicit FloatSize(const LayoutSize&);
 
     static FloatSize narrowPrecision(double width, double height);
 
     float width() const { return m_width; }
     float height() const { return m_height; }
 
     void setWidth(float width) { m_width = width; }
     void setHeight(float height) { m_height = height; }
@@ skipping 141 matching lines @@
     return IntPoint(clampTo<int>(floorf(p.width())), clampTo<int>(floorf(p.height())));
 }
 
 // Redeclared here to avoid ODR issues.
 // See platform/testing/GeometryPrinters.h.
 void PrintTo(const FloatSize&, std::ostream*);
 
 } // namespace blink
 
 #endif // FloatSize_h