wtf/CheckedArithmetic.h delegates to base/numerics/safe_math.h.

third_party/WebKit/Source/wtf/StdLibExtras.h

Index: third_party/WebKit/Source/wtf/StdLibExtras.h
diff --git a/third_party/WebKit/Source/wtf/StdLibExtras.h b/third_party/WebKit/Source/wtf/StdLibExtras.h
index efaa3c65142fedce8a99dce73595bc5f6fac15b7..90230f42d3519f662ef09cd3abe1a91fcac7f805 100644
--- a/third_party/WebKit/Source/wtf/StdLibExtras.h
+++ b/third_party/WebKit/Source/wtf/StdLibExtras.h
@@ -28,7 +28,7 @@
 
 #include "wtf/Assertions.h"
 #include "wtf/CPU.h"
-#include "wtf/CheckedArithmetic.h"
+#include "wtf/CheckedNumeric.h"
 #include "wtf/LeakAnnotations.h"
 #include <cstddef>
 
@@ -153,8 +153,8 @@ inline TO bitwise_cast(FROM from)
 template<typename To, typename From>
 inline To safeCast(From value)
 {
-    RELEASE_ASSERT(isInBounds<To>(value));
-    return static_cast<To>(value);
+    CheckedNumeric<To> checked(value);
+    return checked.ValueOrDie();

[dcheng, 2016/03/17 08:25:14]

checked_cast is the //base/numerics/safe_conversions.h equivalent.

[Bret, 2016/03/18 20:48:51]

Done.

 }
 
 // Use the following macros to prevent errors caused by accidental