ipc: Create AttachmentBrokerPrivileged and AttachmentBrokerUnprivileged.

This CL is a refactor and contains no behavior changes.

AttachmentBroker is an abstract base class. I made two new abstract subclasses,
AttachmentBrokerPrivileged and AttachmentBrokerUnprivileged for use in
privileged and unprivileged processes respectively. These in turn are inherited
by AttachmentBrokerPrivilegedWin and AttachmentBrokerUnprivilegedWin.

BUG=493414
[email protected]

Review URL: https://codereview.chromium.org/1256993003

Cr-Commit-Position: refs/heads/master@{#340803}
diff --git a/ipc/BUILD.gn b/ipc/BUILD.gn
index 75d0c626..c56559f 100644
--- a/ipc/BUILD.gn
+++ b/ipc/BUILD.gn
@@ -9,10 +9,14 @@
     "attachment_broker.cc",
     "attachment_broker.h",
     "attachment_broker_messages.h",
+    "attachment_broker_privileged.cc",
+    "attachment_broker_privileged.h",
     "attachment_broker_privileged_win.cc",
     "attachment_broker_privileged_win.h",
-    "attachment_broker_win.cc",
-    "attachment_broker_win.h",
+    "attachment_broker_unprivileged.cc",
+    "attachment_broker_unprivileged.h",
+    "attachment_broker_unprivileged_win.cc",
+    "attachment_broker_unprivileged_win.h",
     "brokerable_attachment.cc",
     "brokerable_attachment.h",
     "handle_attachment_win.cc",
@@ -120,7 +124,7 @@
   test("ipc_tests") {
     sources = [
       "attachment_broker_privileged_win_unittest.cc",
-      "attachment_broker_win_unittest.cc",
+      "attachment_broker_unprivileged_win_unittest.cc",
       "ipc_channel_posix_unittest.cc",
       "ipc_channel_reader_unittest.cc",
       "ipc_channel_unittest.cc",