Disallow cast/implicit conversion from LayoutUnit to int/unsigned

third_party/WebKit/Source/platform/LayoutUnit.h

 /*
  * Copyright (c) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 89 matching lines @@
     {
         float floatValue = toFloat();
         if (static_cast<int>(floatValue * kFixedPointDenominator) == m_value)
             return floatValue;
         if (floatValue > 0)
             return nextafterf(floatValue, std::numeric_limits<float>::max());
         return nextafterf(floatValue, std::numeric_limits<float>::min());
     }
     unsigned toUnsigned() const { REPORT_OVERFLOW(m_value >= 0); return toInt(); }
 
-    operator int() const { return toInt(); }
-    operator unsigned() const { return toUnsigned(); }
+    // Conversion to int or unsigned is lossy. 'explicit' on these operators won't work because
+    // there are also other implicit conversion paths (e.g. operator bool then to int which would
+    // generate wrong result). Use toInt() and toUnsigned() instead.
+    operator int() const = delete;
+    operator unsigned() const = delete;
+
     operator double() const { return toDouble(); }
     operator float() const { return toFloat(); }
     operator bool() const { return m_value; }
 
     LayoutUnit operator++(int)
     {
         m_value += kFixedPointDenominator;
         return *this;
     }
 
@@ skipping 689 matching lines @@
 }
 
 inline std::ostream& operator<<(std::ostream& stream, const LayoutUnit& value)
 {
     return stream << value.toString();
 }
 
 } // namespace blink
 
 #endif // LayoutUnit_h