Delete osp_base and move files to new homes

This patch is the second and major patch in the process of removing the
osp_base folder from Open Screen. Based on the design plan here:

https://docs.google.com/document/d/1LGV8tXdDeIH38MYlNF2XJNG49pec-64nWkS0jjnJNk4/edit#heading=h.ny8tc2v4ek9m

This patch moves most of the files in osp_base to new homes in platform,
excepting files that have been moved to the new util/ folder.

Change-Id: I6e5f1d13cf20806bcc41185a842eb0b293606306
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/1695736
Reviewed-by: Jordan Bayles <jophba@chromium.org>
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Commit-Queue: Jordan Bayles <jophba@chromium.org>
diff --git a/platform/api/udp_socket.h b/platform/api/udp_socket.h
index e648124..7ac9035 100644
--- a/platform/api/udp_socket.h
+++ b/platform/api/udp_socket.h
@@ -9,10 +9,10 @@
 #include <functional>
 #include <memory>
 
-#include "osp_base/error.h"
-#include "osp_base/ip_address.h"
-#include "osp_base/macros.h"
 #include "platform/api/network_interface.h"
+#include "platform/base/error.h"
+#include "platform/base/ip_address.h"
+#include "platform/base/macros.h"
 
 namespace openscreen {
 namespace platform {