Use DiscardableMemoryManager on Android.

base/base.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.
 
 {
   'target_defaults': {
     'variables': {
       'base_target': 0,
       'base_i18n_target': 0,
     },
@@ skipping 752 matching lines @@
                'rand_util_posix.cc',
                'scoped_native_library.cc',
                'files/scoped_temp_dir.cc',
                'sys_info_posix.cc',
                'third_party/dynamic_annotations/dynamic_annotations.c',
             ],
             'sources/': [
               ['include', '^threading/platform_thread_linux\\.cc$'],
             ],
           }],
+          ['OS == "android" and _toolset == "target"', {
+           'sources': [
+             'memory/discardable_memory_ashmem.cc',
+             'memory/discardable_memory_ashmem.h',
+           ],
+          }],
           ['OS == "android" and >(nacl_untrusted_build)==0', {
             'sources!': [
               'base_paths_posix.cc',
               'files/file_path_watcher_kqueue.cc',
               'files/file_path_watcher_stub.cc',
               'power_monitor/power_monitor_device_source_posix.cc',
             ],
             'sources/': [
               ['include', '^debug/proc_maps_linux\\.cc$'],
               ['include', '^files/file_path_watcher_linux\\.cc$'],
@@ skipping 172 matching lines @@
           'i18n/time_formatting.h',
           'i18n/timezone.cc',
           'i18n/timezone.h',
           'i18n/utf8_validator_tables.cc',
           'i18n/utf8_validator_tables.h',
         ],
       }]
     ],
   },
 }