Add ExcServerCopyState()

util/mach/exc_server_variants.cc

Index: util/mach/exc_server_variants.cc
diff --git a/util/mach/exc_server_variants.cc b/util/mach/exc_server_variants.cc
index 6e5cd3f2ec6d0efd789f1bf6a3e8bd31d5db88a2..b6e046a4ab6118362f5e1d8f5be67f01774c9258 100644
--- a/util/mach/exc_server_variants.cc
+++ b/util/mach/exc_server_variants.cc
@@ -14,6 +14,8 @@
 
 #include "util/mach/exc_server_variants.h"
 
+#include <string.h>
+
 #include <algorithm>
 #include <vector>
 
@@ -801,4 +803,15 @@ kern_return_t ExcServerSuccessfulReturnValue(exception_behavior_t behavior,
   return KERN_SUCCESS;
 }
 
+void ExcServerCopyState(exception_behavior_t behavior,
+                        const natural_t* old_state,
+                        mach_msg_type_number_t old_state_count,
+                        thread_state_t new_state,
+                        mach_msg_type_number_t* new_state_count) {
+  if (ExceptionBehaviorHasState(behavior)) {
+    *new_state_count = std::min(old_state_count, *new_state_count);
+    memcpy(new_state, old_state, *new_state_count * sizeof(old_state[0]));
+  }
+}
+
 }  // namespace crashpad