Implement basic stack traces on Android and reenable unit tests.

base/base.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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'includes': [
     '../build/win_precompile.gypi',
@@ skipping 653 matching lines @@
           'dependencies': [
             'android/jni_generator/jni_generator.gyp:jni_generator_tests',
           ],
           'conditions': [
             ['gtest_target_type == "shared_library"', {
               'dependencies': [
                 '../testing/android/native_test.gyp:native_test_native_code',
               ],
             }],
           ],
-          'sources!': [
-            # Broken on Android, and already disabled there.
-            'debug/stack_trace_unittest.cc',
-          ],
         }],
         ['OS == "ios" and _toolset != "host"', {
           'sources/': [
             # Only test the iOS-meaningful portion of process_utils.
             ['exclude', '^process_util_unittest'],
             ['include', '^process_util_unittest_ios\\.cc$'],
             # Requires spawning processes.
             ['exclude', '^metrics/stats_table_unittest\\.cc$'],
             # iOS does not use message_pump_libevent.
             ['exclude', '^message_pump_libevent_unittest\\.cc$'],
@@ skipping 573 matching lines @@
             'base_unittests.isolate',
           ],
           'sources': [
             'base_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }