diff --git a/base/mach_ipc_mac.h b/base/mach_ipc_mac.h
index 7e9839c..1e88279 100644
--- a/base/mach_ipc_mac.h
+++ b/base/mach_ipc_mac.h
@@ -70,6 +70,8 @@
 #define PRINT_MACH_RESULT(result_, message_) \
   printf(message_" %s (%d)\n", mach_error_string(result_), result_ );
 
+namespace base {
+
 //==============================================================================
 // A wrapper class for mach_msg_port_descriptor_t (with same memory layout)
 // with convenient constructors and accessors
@@ -319,4 +321,6 @@
   DISALLOW_COPY_AND_ASSIGN(MachPortSender);
 };
 
+}  // namespace base
+
 #endif // BASE_MACH_IPC_MAC_H_
diff --git a/base/mach_ipc_mac.mm b/base/mach_ipc_mac.mm
index fc78bcc..973b66a 100644
--- a/base/mach_ipc_mac.mm
+++ b/base/mach_ipc_mac.mm
@@ -9,6 +9,8 @@
 #include <stdio.h>
 #include "base/logging.h"
 
+namespace base {
+
 //==============================================================================
 MachSendMessage::MachSendMessage(int32_t message_id) : MachMessage() {
   Initialize(message_id);
@@ -306,3 +308,5 @@
 
   return result;
 }
+
+}  // namespace base