bpf_dsl: Move {Bool,Result}ExprImpl definition into separate header

sandbox/linux/sandbox_linux.gypi

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'conditions': [
       ['OS=="linux"', {
         'compile_suid_client': 1,
         'compile_credentials': 1,
@@ skipping 102 matching lines @@
           ],
         }],
       ],
     },
     {
       'target_name': 'seccomp_bpf',
       'type': '<(component)',
       'sources': [
         'bpf_dsl/bpf_dsl.cc',
         'bpf_dsl/bpf_dsl.h',
+        'bpf_dsl/bpf_dsl_impl.h',
         'bpf_dsl/cons.h',
         'seccomp-bpf/basicblock.cc',
         'seccomp-bpf/basicblock.h',
         'seccomp-bpf/codegen.cc',
         'seccomp-bpf/codegen.h',
         'seccomp-bpf/die.cc',
         'seccomp-bpf/die.h',
         'seccomp-bpf/errorcode.cc',
         'seccomp-bpf/errorcode.h',
         'seccomp-bpf/instruction.h',
@@ skipping 208 matching lines @@
             '../../build/isolate.gypi',
           ],
           'sources': [
             '../sandbox_linux_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }