MachMessageServer: Make request messages const

util/mach/exc_server_variants.h

Index: util/mach/exc_server_variants.h
diff --git a/util/mach/exc_server_variants.h b/util/mach/exc_server_variants.h
index 08e770aabbe395918c468d836abd5209579f346c..81651cec7a5f6451a1a22cf8cf50883f56d9edb2 100644
--- a/util/mach/exc_server_variants.h
+++ b/util/mach/exc_server_variants.h
@@ -104,7 +104,7 @@ class ExcServer : public MachMessageServer::Interface {
   // MachMessageServer::Interface:
 
   virtual bool MachMessageServerFunction(
-      mach_msg_header_t* in_header,
+      const mach_msg_header_t* in_header,
       mach_msg_header_t* out_header,
       bool* destroy_complex_request) override;
 
@@ -192,7 +192,7 @@ class MachExcServer : public MachMessageServer::Interface {
   // MachMessageServer::Interface:
 
   virtual bool MachMessageServerFunction(
-      mach_msg_header_t* in_header,
+      const mach_msg_header_t* in_header,
       mach_msg_header_t* out_header,
       bool* destroy_complex_request) override;
 
@@ -402,7 +402,7 @@ class UniversalMachExcServer
   // MachMessageServer::Interface:
 
   virtual bool MachMessageServerFunction(
-      mach_msg_header_t* in_header,
+      const mach_msg_header_t* in_header,
       mach_msg_header_t* out_header,
       bool* destroy_complex_request) override;