mac: Remove some 10.6-SDK-only sandbox code.

sandbox/mac/xpc_message_server_unittest.cc

Index: sandbox/mac/xpc_message_server_unittest.cc
diff --git a/sandbox/mac/xpc_message_server_unittest.cc b/sandbox/mac/xpc_message_server_unittest.cc
index 585a627c5122e1711335cc0fa992f3bffd56ba49..16872901993c15a611055905b0dc3be3d22ac0c0 100644
--- a/sandbox/mac/xpc_message_server_unittest.cc
+++ b/sandbox/mac/xpc_message_server_unittest.cc
@@ -26,7 +26,6 @@ class XPCMessageServerTest : public testing::Test {
   void SetUp() override {
     if (!RunXPCTest())
       return;
-    ASSERT_TRUE(InitializeXPC());
   }
 
   bool RunXPCTest() {
@@ -180,8 +179,6 @@ XPC_TEST_F(GetSenderPID)  // {
 }
 
 MULTIPROCESS_TEST_MAIN(GetSenderPID) {
-  CHECK(sandbox::InitializeXPC());
-
   mach_port_t port = MACH_PORT_NULL;
   CHECK_EQ(KERN_SUCCESS, bootstrap_look_up(bootstrap_port, kGetSenderPID,
       &port));