Remove old system_wrappers event_tracer.h.

webrtc/system_wrappers/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("//build/config/android/config.gni")
 import("../build/webrtc.gni")
 
 static_library("system_wrappers") {
   sources = [
     "include/aligned_array.h",
     "include/aligned_malloc.h",
     "include/atomic32.h",
     "include/clock.h",
     "include/condition_variable_wrapper.h",
     "include/cpu_features_wrapper.h",
     "include/cpu_info.h",
     "include/critical_section_wrapper.h",
     "include/data_log.h",
     "include/data_log_c.h",
     "include/data_log_impl.h",
-    "include/event_tracer.h",
     "include/event_wrapper.h",
     "include/field_trial.h",
     "include/file_wrapper.h",
     "include/fix_interlocked_exchange_pointer_win.h",
     "include/logging.h",
     "include/metrics.h",
     "include/ref_count.h",
     "include/rtp_to_ntp.h",
     "include/rw_lock_wrapper.h",
     "include/scoped_vector.h",
@@ skipping 24 matching lines @@
     "source/critical_section_posix.cc",
     "source/critical_section_posix.h",
     "source/critical_section_win.cc",
     "source/critical_section_win.h",
     "source/data_log_c.cc",
     "source/event.cc",
     "source/event_timer_posix.cc",
     "source/event_timer_posix.h",
     "source/event_timer_win.cc",
     "source/event_timer_win.h",
-    "source/event_tracer.cc",
     "source/file_impl.cc",
     "source/file_impl.h",
     "source/logging.cc",
     "source/rtp_to_ntp.cc",
     "source/rw_lock.cc",
     "source/rw_lock_generic.cc",
     "source/rw_lock_generic.h",
     "source/rw_lock_posix.cc",
     "source/rw_lock_posix.h",
     "source/rw_lock_win.cc",
@@ skipping 126 matching lines @@
       "source/cpu_features_android.c",
     ]
 
     configs += [ "..:common_config" ]
     public_configs = [ "..:common_inherited_config" ]
     deps = [
       "//third_party/android_tools:cpu_features",
     ]
   }
 }