Add strictly checked numeric types

base/numerics/safe_math.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 BASE_NUMERICS_SAFE_MATH_H_
 #define BASE_NUMERICS_SAFE_MATH_H_
 
 #include "base/numerics/safe_math_impl.h"
 
 namespace base {
@@ skipping 48 matching lines @@
 
   // This is not an explicit constructor because we implicitly upgrade regular
   // numerics to CheckedNumerics to make them easier to use.
   template <typename Src>
   CheckedNumeric(Src value)
       : state_(value) {
     static_assert(std::numeric_limits<Src>::is_specialized,
                   "Argument must be numeric.");
   }
 
+  // This is not an explicit constructor because we want a seamless conversion
+  // from StrictNumeric types.
+  template <typename Src>
+  CheckedNumeric(StrictNumeric<Src> value)
+      : state_(static_cast<Src>(value)) {
+  }
+
   // IsValid() is the public API to test if a CheckedNumeric is currently valid.
   bool IsValid() const { return validity() == RANGE_VALID; }
 
   // ValueOrDie() The primary accessor for the underlying value. If the current
   // state is not valid it will CHECK and crash.
   T ValueOrDie() const {
     CHECK(IsValid());
     return state_.value();
   }
 
@@ skipping 184 matching lines @@
 
 #undef BASE_NUMERIC_ARITHMETIC_OPERATORS
 
 }  // namespace internal
 
 using internal::CheckedNumeric;
 
 }  // namespace base
 
 #endif  // BASE_NUMERICS_SAFE_MATH_H_