Remove remaining base dependencies from base/numerics

base/numerics/safe_conversions.h

Index: base/numerics/safe_conversions.h
diff --git a/base/numerics/safe_conversions.h b/base/numerics/safe_conversions.h
index 4f45caf9c5209592f585445dee9d5fe79dfdd0b5..fb8ef09640cd9ad01133ad8bfa2e11808cad2470 100644
--- a/base/numerics/safe_conversions.h
+++ b/base/numerics/safe_conversions.h
@@ -7,10 +7,10 @@
 
 #include <stddef.h>
 
+#include <cassert>
 #include <limits>
 #include <type_traits>
 
-#include "base/logging.h"
 #include "base/numerics/safe_conversions_impl.h"
 
 namespace base {
@@ -41,11 +41,15 @@ constexpr typename std::enable_if<!std::numeric_limits<T>::is_signed,
   return false;
 }
 
-// Just fires a CHECK(false). Used for numeric boundary errors.
+// Forces a crash, like a CHECK(false). Used for numeric boundary errors.
 struct CheckOnFailure {
   template <typename T>
   static T HandleFailure() {
-    CHECK(false);
+#if defined(__GNUC__) || defined(__clang__)
+    __builtin_trap();
+#else
+    ((void)(*(volatile char*)0 = 0));

[Tom Sepez, 2016/11/22 18:17:31]

I thought we had an issue with some compiler pulling these out due to "undefined
behavior".  But we do the same in partitionAlloc.  We have EXPECT_DEATH tests
for these?

[jschuh, 2016/11/22 18:27:52]

This is exactly what base/logging.h uses for a CHECK in release builds. Maybe
GCC or clang would optimize it out as undefined behavior, but those are using an
explicit trap intrinsic.

+#endif
     return T();
   }
 };
@@ -75,6 +79,7 @@ struct SaturatedCastNaNBehaviorReturnZero {
 namespace internal {
 // This wrapper is used for C++11 constexpr support by avoiding the declaration
 // of local variables in the saturated_cast template function.
+// TODO(jschuh): convert this back to a switch once we support C++14.
 template <typename Dst, class NaNHandler, typename Src>
 constexpr Dst saturated_cast_impl(const Src value,
                                   const RangeConstraint constraint) {
@@ -86,7 +91,7 @@ constexpr Dst saturated_cast_impl(const Src value,
                            ? std::numeric_limits<Dst>::max()
                            : (constraint == RANGE_INVALID
                                   ? NaNHandler::template HandleFailure<Dst>()
-                                  : (NOTREACHED(), static_cast<Dst>(value)))));
+                                  : (assert(false), static_cast<Dst>(value)))));
 }
 }  // namespace internal