Added a whitelist for trace events that are known to be PII-less.

content/content_common.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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../components/tracing.gyp:tracing',
     '../gpu/command_buffer/command_buffer.gyp:gles2_utils',
     '../net/net.gyp:net',
@@ skipping 119 matching lines @@
       'public/common/speech_recognition_error.h',
       'public/common/speech_recognition_grammar.h',
       'public/common/speech_recognition_result.cc',
       'public/common/speech_recognition_result.h',
       'public/common/ssl_status.cc',
       'public/common/ssl_status.h',
       'public/common/stop_find_action.h',
       'public/common/storage_quota_params.h',
       'public/common/three_d_api_types.h',
       'public/common/top_controls_state.h',
+      'public/common/tracing_utils.cc',
+      'public/common/tracing_utils.h',
       'public/common/transition_element.h',
       'public/common/url_constants.cc',
       'public/common/url_constants.h',
       'public/common/url_fetcher.h',
       'public/common/url_utils.cc',
       'public/common/url_utils.h',
       'public/common/user_agent.h',
       'public/common/web_preferences.cc',
       'public/common/web_preferences.h',
       'public/common/webplugininfo.cc',
@@ skipping 901 matching lines @@
         'common/gpu/client/gpu_memory_buffer_impl_ozone.cc',
         'common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc',
         'common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.h',
         'common/gpu/gpu_memory_buffer_factory_ozone.cc',
         'common/gpu/gpu_memory_buffer_factory_ozone_native_buffer.cc',
         'common/gpu/gpu_memory_buffer_factory_ozone_native_buffer.h',
       ],
     }],
   ],
 }