Cleanup dead code in base/ as found by Scythe.

base/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/ui.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 165 matching lines @@
     "debug/trace_event_memory.h",
     "debug/trace_event_synthetic_delay.cc",
     "debug/trace_event_synthetic_delay.h",
     "debug/trace_event_system_stats_monitor.cc",
     "debug/trace_event_system_stats_monitor.h",
     "debug/trace_event_win.cc",
     "deferred_sequenced_task_runner.cc",
     "deferred_sequenced_task_runner.h",
     "environment.cc",
     "environment.h",
-    "event_recorder.h",
-    "event_recorder_stubs.cc",
-    "event_recorder_win.cc",
     "file_descriptor_posix.h",
     "file_version_info.h",
     "file_version_info_mac.h",
     "file_version_info_mac.mm",
     "file_version_info_win.cc",
     "file_version_info_win.h",
     "files/dir_reader_fallback.h",
     "files/dir_reader_linux.h",
     "files/dir_reader_posix.h",
     "files/file.cc",
@@ skipping 650 matching lines @@
       "os_compat_nacl.cc",
       "os_compat_nacl.h",
       "rand_util_nacl.cc",
       "memory/shared_memory_nacl.cc",
     ]
   }
 
   # Windows.
   if (is_win) {
     sources -= [
-      "event_recorder_stubs.cc",
       "message_loop/message_pump_libevent.cc",
       "strings/string16.cc",
 
       # Not using sha1_win.cc because it may have caused a
       # regression to page cycler moz.
       "sha1_win.cc",
     ]
 
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     cflags = [ "/wd4267" ]
@@ skipping 660 matching lines @@
   # GYP: //base.gyp:base_unittests_apk
   unittest_apk("base_unittests_apk") {
     deps = [
       ":base_java",
       ":base_java_unittest_support",
       ":base_unittests",
     ]
     unittests_dep = ":base_unittests"
   }
 }