Fixes for -Wunused-function on Linux, Android and ChromeOS

sandbox/linux/seccomp-bpf/sandbox_bpf.cc

 // Copyright (c) 2012 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.
 
 // Some headers on Android are missing cdefs: crbug.com/172337.
 // (We can't use OS_ANDROID here since build_config.h is not included).
 #if defined(ANDROID)
 #include <sys/cdefs.h>
 #endif
 
@@ skipping 20 matching lines @@
 #include "sandbox/linux/seccomp-bpf/syscall.h"
 #include "sandbox/linux/seccomp-bpf/syscall_iterator.h"
 #include "sandbox/linux/seccomp-bpf/verifier.h"
 
 namespace playground2 {
 
 namespace {
 
 const int kExpectedExitCode = 100;
 
-template <class T>
-int popcount(T x);
-template <>
-int popcount<unsigned int>(unsigned int x) {
+int popcount(uint32_t x) {
   return __builtin_popcount(x);
 }
-template <>
-int popcount<unsigned long>(unsigned long x) {
-  return __builtin_popcountl(x);
-}
-template <>
-int popcount<unsigned long long>(unsigned long long x) {
-  return __builtin_popcountll(x);
-}
 
+#if !defined(NDEBUG)
 void WriteFailedStderrSetupMessage(int out_fd) {
   const char* error_string = strerror(errno);
   static const char msg[] =
       "You have reproduced a puzzling issue.\n"
       "Please, report to crbug.com/152530!\n"
       "Failed to set up stderr: ";
   if (HANDLE_EINTR(write(out_fd, msg, sizeof(msg) - 1)) > 0 && error_string &&
       HANDLE_EINTR(write(out_fd, error_string, strlen(error_string))) > 0 &&
       HANDLE_EINTR(write(out_fd, "\n", 1))) {
   }
 }
+#endif  // !defined(NDEBUG)
 
 // We define a really simple sandbox policy. It is just good enough for us
 // to tell that the sandbox has actually been activated.
 ErrorCode ProbeEvaluator(Sandbox*, int sysnum, void*) __attribute__((const));
 ErrorCode ProbeEvaluator(Sandbox*, int sysnum, void*) {
   switch (sysnum) {
     case __NR_getpid:
       // Return EPERM so that we can check that the filter actually ran.
       return ErrorCode(EPERM);
     case __NR_exit_group:
@@ skipping 943 matching lines @@
                    &*conds_->insert(failed).first);
 }
 
 ErrorCode Sandbox::Kill(const char* msg) {
   return Trap(BpfFailure, const_cast<char*>(msg));
 }
 
 Sandbox::SandboxStatus Sandbox::status_ = STATUS_UNKNOWN;
 
 }  // namespace playground2