restore LOG_FATAL crash key on windows

chrome/common/child_process_logging_win.cc

 // 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.
 
 #include "chrome/common/child_process_logging.h"
 
 #include <windows.h>
 
 #include <memory>
 
+#include "base/auto_reset.h"
 #include "base/debug/crash_logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/crash_keys.h"
 #include "chrome/installer/util/google_update_settings.h"
 #include "components/metrics/client_info.h"
 
 namespace child_process_logging {
 
 namespace {
@@ skipping 24 matching lines @@
   static ClearCrashKeyValue clear_crash_key = []() {
     HMODULE elf_module = GetModuleHandle(chrome::kChromeElfDllName);
     return reinterpret_cast<ClearCrashKeyValue>(
         elf_module ? GetProcAddress(elf_module, "ClearCrashKeyValueImpl")
                    : nullptr);
   }();
   if (clear_crash_key)
     (clear_crash_key)(base::UTF8ToWide(key).data());
 }
 
+// Please keep synced with one in crashpad.cc.
+void CrashMessageHandler(const std::string& message) {
+  // In case of an out-of-memory condition, this code could be reentered when
+  // constructing and storing the key. Using a static is not thread-safe, but
+  // if multiple threads are in the process of a fatal crash at the same time,
+  // this should work.
+  static bool guarded = false;
+  if (!guarded) {
+    base::AutoReset<bool> guard(&guarded, true);
+    base::debug::SetCrashKeyValue("LOG_FATAL", message);
+  }
+}
+
 }  // namespace
 
 void Init() {
   base::debug::SetCrashKeyReportingFunctions(&SetCrashKeyValueTrampoline,
                                              &ClearCrashKeyValueTrampoline);
+  logging::SetCrashMessageHandler(CrashMessageHandler);
 
   // This would be handled by BreakpadClient::SetCrashClientIdFromGUID(), but
   // because of the aforementioned issue, crash keys aren't ready yet at the
   // time of Breakpad initialization, load the client id backed up in Google
   // Update settings instead.
   // Please note if we are using Crashpad via chrome_elf then we need to call
   // into chrome_elf to pass in the client id.
   std::unique_ptr<metrics::ClientInfo> client_info =
       GoogleUpdateSettings::LoadMetricsClientInfo();
 
@@ skipping 21 matching lines @@
   } else {
     // TODO(ananta)
     // Remove this when the change to not require crash key registration lands.
     crash_keys::RegisterChromeCrashKeys();
     if (client_info)
       crash_keys::SetMetricsClientIdFromGUID(client_info->client_id);
   }
 }
 
 }  // namespace child_process_logging