zip: Add ZipReader and rework Unzip() using the new class.

chrome/chrome_tests.gypi

 # Copyright (c) 2011 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' : {
     # Variables for js2gtest rules
     'gypv8sh': '../tools/gypv8sh.py',
     'js2gtest': 'test/base/js2gtest.js',
     'js2gtest_out_dir': '<(SHARED_INTERMEDIATE_DIR)/js2gtest',
     'mock_js': 'third_party/mock4js/mock4js.js',
@@ skipping 1913 matching lines @@
         'common/net/gaia/google_service_auth_error_unittest.cc',
         'common/net/gaia/oauth_request_signer_unittest.cc',
         'common/random_unittest.cc',
         'common/service_process_util_unittest.cc',
         'common/string_ordinal_unittest.cc',
         'common/switch_utils_unittest.cc',
         'common/thumbnail_score_unittest.cc',
         'common/time_format_unittest.cc',
         'common/web_apps_unittest.cc',
         'common/worker_thread_ticker_unittest.cc',
+        'common/zip_reader_unittest.cc',
         'common/zip_unittest.cc',
         'renderer/extensions/chrome_v8_context_set_unittest.cc',
         'renderer/extensions/extension_api_json_validity_unittest.cc',
         'renderer/extensions/json_schema_unittest.cc',
         'renderer/net/predictor_queue_unittest.cc',
         'renderer/net/renderer_predictor_unittest.cc',
         'renderer/plugin_uma_unittest.cc',
         'renderer/renderer_about_handler_unittest.cc',
         'renderer/safe_browsing/features_unittest.cc',
         'renderer/safe_browsing/murmurhash3_util_unittest.cc',
@@ skipping 2322 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],  # 'coverage!=0'
   ],  # 'conditions'
 }