Use task_t, thread_t, and exception_handler_t uniformly

util/mach/task_memory.h

Index: util/mach/task_memory.h
diff --git a/util/mach/task_memory.h b/util/mach/task_memory.h
index 374f3304dbf7575fc5f75737d3b4a490df389100..cd1adf96d4ab6d55257ea30f5ea3f2054768dd3c 100644
--- a/util/mach/task_memory.h
+++ b/util/mach/task_memory.h
@@ -88,7 +88,7 @@ class TaskMemory {
 
   //! \param[in] task A send right to the target task’s task port. This object
   //!     does not take ownership of the send right.
-  explicit TaskMemory(mach_port_t task);
+  explicit TaskMemory(task_t task);
 
   ~TaskMemory() {}
 
@@ -167,7 +167,7 @@ class TaskMemory {
                            mach_vm_size_t size,
                            std::string* string);
 
-  mach_port_t task_;  // weak
+  task_t task_;  // weak
 
   DISALLOW_COPY_AND_ASSIGN(TaskMemory);
 };