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

util/win/process_info_test.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,
@@ skipping 13 matching lines @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "gtest/gtest.h"
 #include "test/errors.h"
 #include "test/scoped_temp_dir.h"
 #include "test/paths.h"
 #include "test/win/child_launcher.h"
 #include "util/file/file_io.h"
 #include "util/misc/uuid.h"
+#include "util/win/get_function.h"
 #include "util/win/scoped_handle.h"
 
 namespace crashpad {
 namespace test {
 namespace {
 
 const wchar_t kNtdllName[] = L"\\ntdll.dll";
 
 bool IsProcessWow64(HANDLE process_handle) {
-  static decltype(IsWow64Process)* is_wow64_process =
-      reinterpret_cast<decltype(IsWow64Process)*>(
-          GetProcAddress(LoadLibrary(L"kernel32.dll"), "IsWow64Process"));
+  static const auto is_wow64_process =
+      GET_FUNCTION(L"kernel32.dll", ::IsWow64Process);
   if (!is_wow64_process)
     return false;
   BOOL is_wow64;
   if (!is_wow64_process(process_handle, &is_wow64)) {
     PLOG(ERROR) << "IsWow64Process";
     return false;
   }
   return is_wow64;
 }
 
@@ skipping 563 matching lines @@
     }
   }
   EXPECT_TRUE(found_file_handle);
   EXPECT_TRUE(found_key_handle);
   EXPECT_TRUE(found_mapping_handle);
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad