Fix silent truncations when extracting values from CheckedNumeric

components/nacl/browser/pnacl_host.cc

Index: components/nacl/browser/pnacl_host.cc
diff --git a/components/nacl/browser/pnacl_host.cc b/components/nacl/browser/pnacl_host.cc
index 1dacf669a9ea96ae519c28607b1698c35e7958a0..605d7d71d049fe9dd14c96765da8cbff55027f25 100644
--- a/components/nacl/browser/pnacl_host.cc
+++ b/components/nacl/browser/pnacl_host.cc
@@ -418,8 +418,8 @@ scoped_refptr<net::DrainableIOBuffer> PnaclHost::CopyFileToBuffer(
   }
 
   buffer = new net::DrainableIOBuffer(
-      new net::IOBuffer(base::CheckedNumeric<size_t>(file_size).ValueOrDie()),
-      base::CheckedNumeric<size_t>(file_size).ValueOrDie());
+      new net::IOBuffer(base::checked_cast<size_t>(file_size)),
+      base::checked_cast<size_t>(file_size));
   if (file->Read(0, buffer->data(), buffer->size()) != file_size) {
     PLOG(ERROR) << "CopyFileToBuffer file read failed";
     buffer = nullptr;