Rework UMAHistogramHelper and StatisticsDeltaReader into [Chrome]HistogramTester.

chrome/chrome_tests_unit.gypi

 # Copyright 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': [
     {
       # This target contains mocks and test utilities that don't belong in
       # production libraries but are used by more than one test executable.
       'target_name': 'test_support_common',
       'type': 'static_library',
@@ skipping 252 matching lines @@
         'test/base/testing_pref_service_syncable.cc',
         'test/base/testing_pref_service_syncable.h',
         'test/base/testing_profile.cc',
         'test/base/testing_profile.h',
         'test/base/testing_profile_manager.cc',
         'test/base/testing_profile_manager.h',
         'test/base/tracing.cc',
         'test/base/tracing.h',
         'test/base/ui_test_utils.cc',
         'test/base/ui_test_utils.h',
-        'test/base/uma_histogram_helper.cc',
-        'test/base/uma_histogram_helper.h',
         'test/logging/win/file_logger.cc',
         'test/logging/win/file_logger.h',
         'test/logging/win/log_file_printer.cc',
         'test/logging/win/log_file_printer.h',
         'test/logging/win/log_file_reader.cc',
         'test/logging/win/log_file_reader.h',
         'test/logging/win/mof_data_parser.cc',
         'test/logging/win/mof_data_parser.h',
         'test/logging/win/test_log_collector.cc',
         'test/logging/win/test_log_collector.h',
@@ skipping 2632 matching lines @@
             'unit_tests.isolate',
           ],
           'sources': [
             'unit_tests.isolate',
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }