Fix some potential Mach port leaks from mach_host_self using a new ScopedMachPort class.

base/sys_info_mac.cc

Index: base/sys_info_mac.cc
diff --git a/base/sys_info_mac.cc b/base/sys_info_mac.cc
index 3a936890342b94d37ddccdad1d5f19ecfe28785a..8ed02905b1b95a7694cbd8c96d327a2e7d397eec 100644
--- a/base/sys_info_mac.cc
+++ b/base/sys_info_mac.cc
@@ -12,6 +12,7 @@
 #include <sys/types.h>
 
 #include "base/logging.h"
+#include "base/mac/scoped_mach_port.h"
 #include "base/stringprintf.h"
 
 namespace base {
@@ -44,7 +45,8 @@ void SysInfo::OperatingSystemVersionNumbers(int32* major_version,
 int64 SysInfo::AmountOfPhysicalMemory() {
   struct host_basic_info hostinfo;
   mach_msg_type_number_t count = HOST_BASIC_INFO_COUNT;
-  int result = host_info(mach_host_self(),
+  base::mac::ScopedMachPort host(mach_host_self());
+  int result = host_info(host,
                          HOST_BASIC_INFO,
                          reinterpret_cast<host_info_t>(&hostinfo),
                          &count);