Make base_unittests_apk actually work

tools/android/md5sum/md5sum.gyp

 # 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.
 
 {
   'targets': [
     {
+      # GN: //tools/android/md5sum:md5sum
       'target_name': 'md5sum',
       'type': 'none',
       'dependencies': [
         'md5sum_stripped_device_bin',
         'md5sum_bin_host#host',
       ],
       # For the component build, ensure dependent shared libraries are stripped
       # and put alongside md5sum to simplify pushing to the device.
       'variables': {
          'output_dir': '<(PRODUCT_DIR)/md5sum_dist/',
          'native_binary': '<(PRODUCT_DIR)/md5sum_bin',
       },
       'includes': ['../../../build/android/native_app_dependencies.gypi'],
     },
     {
+      # GN: //tools/android/md5sum:md5sum_bin($default_toolchain)
       'target_name': 'md5sum_device_bin',
       'type': 'executable',
       'dependencies': [
         '../../../base/base.gyp:base',
       ],
       'include_dirs': [
         '../../..',
       ],
       'sources': [
         'md5sum.cc',
       ],
       'conditions': [
         [ 'order_profiling!=0 and OS=="android"', {
             'dependencies': [ '../../../tools/cygprofile/cygprofile.gyp:cygprofile', ],
         }],
       ],
     },
     {
+      # GN: //tools/android/md5sum:md5sum_prepare_dist
       'target_name': 'md5sum_stripped_device_bin',
       'type': 'none',
       'dependencies': [
         'md5sum_device_bin',
       ],
       'actions': [
         {
           'action_name': 'strip_md5sum_device_bin',
           'inputs': ['<(PRODUCT_DIR)/md5sum_device_bin'],
           'outputs': ['<(PRODUCT_DIR)/md5sum_bin'],
           'action': [
             '<(android_strip)',
             '--strip-unneeded',
             '<@(_inputs)',
             '-o',
             '<@(_outputs)',
           ],
         },
       ],
     },
     # Same binary but for the host rather than the device.
     {
+      # GN: //tools/android/md5sum:md5sum_copy_host($default_toolchain)
       'target_name': 'md5sum_bin_host',
       'toolsets': ['host'],
       'type': 'executable',
       'dependencies': [
         '../../../base/base.gyp:base',
       ],
       'include_dirs': [
         '../../..',
       ],
       'sources': [
         'md5sum.cc',
       ],
     },
   ],
 }