Fixing remaining VC++ 2015 64-bit build breaks

ipc/ipc_perftest_support.cc

Index: ipc/ipc_perftest_support.cc
diff --git a/ipc/ipc_perftest_support.cc b/ipc/ipc_perftest_support.cc
index 3af0a1fa948bc567962d8be9c66323f5bc1bd746..2ece5e1f11f10c43dc8ee749332d4b13e04d132f 100644
--- a/ipc/ipc_perftest_support.cc
+++ b/ipc/ipc_perftest_support.cc
@@ -348,7 +348,7 @@ scoped_refptr<base::TaskRunner> PingPongTestClient::task_runner() {
 LockThreadAffinity::LockThreadAffinity(int cpu_number)
     : affinity_set_ok_(false) {
 #if defined(OS_WIN)
-  const DWORD_PTR thread_mask = 1 << cpu_number;
+  const DWORD_PTR thread_mask = static_cast<DWORD_PTR>(1) << cpu_number;

[Will Harris, 2015/11/10 18:05:14]

will 1U work instead? seems bizarre to cast a literal.

[brucedawson, 2015/11/10 18:43:26]

I asked this on c-users. I could use 1LLU but that is particularly bad in this
case because it is always a 64-bit value and we want sizeof(void*) value.

Their best suggestion was actually DWORD_PTR{1} (uniform initialization syntax)
but that is currently prohibited in Chrome, and not everyone agreed that that
was a great idea.

[Will Harris, 2015/11/10 19:45:45]

okay. makes sense.

   old_affinity_ = SetThreadAffinityMask(GetCurrentThread(), thread_mask);
   affinity_set_ok_ = old_affinity_ != 0;
 #elif defined(OS_LINUX)