ipc: Add the class HandleWin.

HandleWin is a wrapper around a Windows HANDLE that can be transported across
IPC channels that support attachment brokering. The attachment broker is
responsible for duplicating the HANDLE into the destination process.

BUG=493414

Review URL: https://codereview.chromium.org/1281083004

Cr-Commit-Position: refs/heads/master@{#342897}
diff --git a/ipc/BUILD.gn b/ipc/BUILD.gn
index eb592743..2fe70bb 100644
--- a/ipc/BUILD.gn
+++ b/ipc/BUILD.gn
@@ -21,6 +21,8 @@
     "brokerable_attachment.h",
     "handle_attachment_win.cc",
     "handle_attachment_win.h",
+    "handle_win.cc",
+    "handle_win.h",
     "ipc_channel.cc",
     "ipc_channel.h",
     "ipc_channel_common.cc",