Remove CHECK around duplicate FLAG lookup.

webrtc/base/flags.cc

 /*
  *  Copyright 2006 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.
  */
 
@@ skipping 239 matching lines @@
     }
     *argc = j;
   }
 
   // parsed all flags successfully
   return 0;
 }
 
 void FlagList::Register(Flag* flag) {
   assert(flag != NULL && strlen(flag->name()) > 0);
-  RTC_CHECK(!Lookup(flag->name())) << "flag " << flag->name()
-                                   << " declared twice";
+  // NOTE: Don't call Lookup() within Register because it accesses the name_
+  // of other flags in list_, and if the flags are coming from two different
+  // compilation units, the initialization order between them is undefined, and
+  // this will trigger an asan initialization-order-fiasco error.
   flag->next_ = list_;
   list_ = flag;
 }
 
 #if defined(WEBRTC_WIN)
 WindowsCommandLineArguments::WindowsCommandLineArguments() {
   // start by getting the command line.
   LPTSTR command_line = ::GetCommandLine();
    // now, convert it to a list of wide char strings.
   LPWSTR *wide_argv = ::CommandLineToArgvW(command_line, &argc_);
@@ skipping 16 matching lines @@
   // need to free each string in the array, and then the array.
   for(int i = 0; i < argc_; i++) {
     delete[] argv_[i];
   }
 
   delete[] argv_;
 }
 #endif  // WEBRTC_WIN
 
 }  // namespace rtc