Use double cast to avoid VS 2015 64-bit warning

sandbox/win/src/process_policy_test.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 <memory>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 266 matching lines @@
                        L"ProcessPolicyTest_%08x", pid);
   if (-1 != res) {
     return std::wstring(buff);
   }
   return std::wstring();
 }
 
 // This is the function that is called when testing thread creation.
 // It is expected to set an event that the caller is waiting on.
 DWORD TestThreadFunc(LPVOID lpdwThreadParam) {
-  std::wstring event_name =
-      GenerateEventName(reinterpret_cast<DWORD>(lpdwThreadParam));
+  std::wstring event_name = GenerateEventName(
+      static_cast<DWORD>(reinterpret_cast<uintptr_t>(lpdwThreadParam)));
   if (!event_name.length()) {
     return 1;
   }
   HANDLE event = ::OpenEvent(EVENT_ALL_ACCESS | EVENT_MODIFY_STATE, FALSE,
                              event_name.c_str());
   if (!event) {
     return 1;
   }
   if (!SetEvent(event)) {
     return 1;
   }
   return 0;
 }
 
 SBOX_TESTS_COMMAND int Process_CreateThread(int argc, wchar_t** argv) {
   DWORD pid = ::GetCurrentProcessId();
   std::wstring event_name = GenerateEventName(pid);
   if (!event_name.length()) {
     return SBOX_TEST_FIRST_ERROR;
   }
   HANDLE event = ::CreateEvent(NULL, TRUE, FALSE, event_name.c_str());
   if (!event) {
     return SBOX_TEST_SECOND_ERROR;
   }
 
   DWORD thread_id = 0;
   HANDLE thread = NULL;
   thread = ::CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&TestThreadFunc,
                           reinterpret_cast<LPVOID>(pid), 0, &thread_id);

[Nico, 2016/02/10 23:48:12]

this should have a double cast too then – else this happens to work on
little-endian but isn't quite right

[brucedawson, 2016/02/11 00:02:54]

Little versus big endian shouldn't matter. However, I guess we must have C4312
disabled in this project because there's no warning, but adding the double casts
seems reasonable. It will make enabling C4312 easier in the future.

 
   if (!thread) {
     return SBOX_TEST_THIRD_ERROR;
   }
   if (!thread_id) {
     return SBOX_TEST_FOURTH_ERROR;
   }
   if (WaitForSingleObject(thread, INFINITE) != WAIT_OBJECT_0) {
     return SBOX_TEST_FIFTH_ERROR;
   }
@@ skipping 166 matching lines @@
   DWORD pid = ::GetCurrentProcessId();
   std::wstring event_name = GenerateEventName(pid);
   ASSERT_STRNE(NULL, event_name.c_str());
   HANDLE event = ::CreateEvent(NULL, TRUE, FALSE, event_name.c_str());
   EXPECT_NE(static_cast<HANDLE>(NULL), event);
 
   DWORD thread_id = 0;
   HANDLE thread = NULL;
   thread = TargetCreateThread(::CreateThread, NULL, 0,
                               (LPTHREAD_START_ROUTINE)&TestThreadFunc,
                               reinterpret_cast<LPVOID>(pid), 0, &thread_id);

[Nico, 2016/02/10 23:48:12]

this too

[brucedawson, 2016/02/11 00:02:54]

Done.

   EXPECT_NE(static_cast<HANDLE>(NULL), thread);
   EXPECT_EQ(WAIT_OBJECT_0, WaitForSingleObject(thread, INFINITE));
   EXPECT_EQ(WAIT_OBJECT_0, WaitForSingleObject(event, INFINITE));
 }
 
 }  // namespace sandbox