Add NewMachPort() and its test, and switch call sites to use it

util/mach/mach_extensions.cc

Index: util/mach/mach_extensions.cc
diff --git a/util/mach/mach_extensions.cc b/util/mach/mach_extensions.cc
index 86ca7bf24b6cb19a80f5461e0d6a011f5324b8e9..97566c97b59dac6facf864f5d3faaf3c44071588 100644
--- a/util/mach/mach_extensions.cc
+++ b/util/mach/mach_extensions.cc
@@ -17,6 +17,7 @@
 #include <AvailabilityMacros.h>
 #include <pthread.h>
 
+#include "base/mac/mach_logging.h"
 #include "util/mac/mac_util.h"
 
 namespace crashpad {
@@ -27,6 +28,17 @@ thread_t MachThreadSelf() {
   return pthread_mach_thread_np(pthread_self());
 }
 
+mach_port_t NewMachPort(mach_port_right_t right) {
+  mach_port_t port;

[Robert Sesek, 2014/12/17 20:06:47]

= MACH_PORT_NULL, and then you can just do MACH_LOG_IF and return port.

+  kern_return_t kr = mach_port_allocate(mach_task_self(), right, &port);
+  if (kr != KERN_SUCCESS) {
+    MACH_LOG(ERROR, kr) << "mach_port_allocate";
+    return MACH_PORT_NULL;
+  }
+
+  return port;
+}
+
 exception_mask_t ExcMaskAll() {
   // This is necessary because of the way that the kernel validates
   // exception_mask_t arguments to