win: Add and use GET_FUNCTION() and GET_FUNCTION_REQUIRED()

util/win/critical_section_with_debug_info.cc

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #include "util/win/critical_section_with_debug_info.h"
 
 #include "base/logging.h"
+#include "util/win/get_function.h"
 
 namespace crashpad {
 
 namespace {
 
 BOOL CrashpadInitializeCriticalSectionEx(
     CRITICAL_SECTION* critical_section,
     DWORD spin_count,
     DWORD flags) {
-  static decltype(InitializeCriticalSectionEx)* initialize_critical_section_ex =
-      reinterpret_cast<decltype(InitializeCriticalSectionEx)*>(GetProcAddress(
-          LoadLibrary(L"kernel32.dll"), "InitializeCriticalSectionEx"));
-  if (!initialize_critical_section_ex) {
-    PLOG(ERROR) << "GetProcAddress";
-    return false;
-  }
+  static const auto initialize_critical_section_ex =
+      GET_FUNCTION_REQUIRED(L"kernel32.dll", ::InitializeCriticalSectionEx);
   bool ret =
       initialize_critical_section_ex(critical_section, spin_count, flags);
   if (!ret) {
     PLOG(ERROR) << "InitializeCriticalSectionEx";
     return false;
   }
   return true;
 }
 
 }  // namespace
@@ skipping 23 matching lines @@
   if (win7_or_lower) {
     InitializeCriticalSection(critical_section);
     return true;
   }
 
   return CrashpadInitializeCriticalSectionEx(
       critical_section, 0, RTL_CRITICAL_SECTION_FLAG_FORCE_DEBUG_INFO);
 }
 
 }  // namespace crashpad