Introduce dchecked_cast, and start using it

webrtc/base/safe_conversions.h

 /*
  *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 // Borrowed from Chromium's src/base/numerics/safe_conversions.h.
 
 #ifndef WEBRTC_BASE_SAFE_CONVERSIONS_H_
 #define WEBRTC_BASE_SAFE_CONVERSIONS_H_
 
 #include <limits>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/safe_conversions_impl.h"
 
 namespace rtc {
 
 // Convenience function that returns true if the supplied value is in range
 // for the destination type.
 template <typename Dst, typename Src>
 inline bool IsValueInRangeForNumericType(Src value) {
   return internal::RangeCheck<Dst>(value) == internal::TYPE_VALID;
 }
 
-// checked_cast<> is analogous to static_cast<> for numeric types,
-// except that it CHECKs that the specified numeric conversion will not
-// overflow or underflow. NaN source will always trigger a CHECK.
+// checked_cast<> and dchecked_cast<> are analogous to static_cast<> for
+// numeric types, except that they [D]CHECK that the specified numeric
+// conversion will not overflow or underflow. NaN source will always trigger
+// the [D]CHECK.
 template <typename Dst, typename Src>
 inline Dst checked_cast(Src value) {
   RTC_CHECK(IsValueInRangeForNumericType<Dst>(value));
   return static_cast<Dst>(value);
 }
+template <typename Dst, typename Src>
+inline Dst dchecked_cast(Src value) {
+  RTC_DCHECK(IsValueInRangeForNumericType<Dst>(value));
+  return static_cast<Dst>(value);
+}
 
 // saturated_cast<> is analogous to static_cast<> for numeric types, except
 // that the specified numeric conversion will saturate rather than overflow or
 // underflow. NaN assignment to an integral will trigger a RTC_CHECK condition.
 template <typename Dst, typename Src>
 inline Dst saturated_cast(Src value) {
   // Optimization for floating point values, which already saturate.
   if (std::numeric_limits<Dst>::is_iec559)
     return static_cast<Dst>(value);
 
@@ skipping 13 matching lines @@
       return std::numeric_limits<Dst>::max();
   }
 
   FATAL();
   return static_cast<Dst>(value);
 }
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_SAFE_CONVERSIONS_H_