Get rid of all pid references from base::SharedMemoryHandle.

base/memory/shared_memory_handle_mac.cc

Index: base/memory/shared_memory_handle_mac.cc
diff --git a/base/memory/shared_memory_handle_mac.cc b/base/memory/shared_memory_handle_mac.cc
index d5c5fbad415d05363678e65f6da76a7197624a2c..3f1d4d83748657a72366535c55aea37d077c3832 100644
--- a/base/memory/shared_memory_handle_mac.cc
+++ b/base/memory/shared_memory_handle_mac.cc
@@ -39,17 +39,14 @@ SharedMemoryHandle::SharedMemoryHandle(mach_vm_size_t size) {
 
   memory_object_ = named_right;
   size_ = size;
-  pid_ = GetCurrentProcId();
   ownership_passes_to_ipc_ = false;
 }
 
 SharedMemoryHandle::SharedMemoryHandle(mach_port_t memory_object,
-                                       mach_vm_size_t size,
-                                       base::ProcessId pid)
+                                       mach_vm_size_t size)
     : type_(MACH),
       memory_object_(memory_object),
       size_(size),
-      pid_(pid),
       ownership_passes_to_ipc_(false) {}
 
 SharedMemoryHandle::SharedMemoryHandle(const SharedMemoryHandle& handle) {
@@ -78,7 +75,7 @@ SharedMemoryHandle SharedMemoryHandle::Duplicate() const {
     }
     case MACH: {
       if (!IsValid())
-        return SharedMemoryHandle(MACH_PORT_NULL, 0, 0);
+        return SharedMemoryHandle();
 
       // Increment the ref count.
       kern_return_t kr = mach_port_mod_refs(mach_task_self(), memory_object_,
@@ -137,7 +134,6 @@ bool SharedMemoryHandle::MapAt(off_t offset,
                      MAP_SHARED, file_descriptor_.fd, offset);
       return *memory != MAP_FAILED;
     case SharedMemoryHandle::MACH:
-      DCHECK_EQ(pid_, GetCurrentProcId());
       kern_return_t kr = mach_vm_map(
           mach_task_self(),
           reinterpret_cast<mach_vm_address_t*>(memory),    // Output parameter
@@ -190,7 +186,6 @@ void SharedMemoryHandle::CopyRelevantData(const SharedMemoryHandle& handle) {
     case MACH:
       memory_object_ = handle.memory_object_;
       size_ = handle.size_;
-      pid_ = handle.pid_;
       ownership_passes_to_ipc_ = handle.ownership_passes_to_ipc_;
       break;
   }