Add some platform abstractions.

(This is a merge of http://go/wvgerrit/70303)

This adds a platform.h file to abstract some of the differences
between Windows and POSIX platforms.  This includes ntohl, setenv,
and ssize_t.

Bug: 122953649
Test: Android Unit Tests
Change-Id: I3235f3f284b53d24d7365ff3f4a06dcd9b403697

libwvdrmengine/cdm/util/include/file_store.h

@@ -7,12 +7,13 @@
 #ifndef WVCDM_UTIL_FILE_STORE_H_
 #define WVCDM_UTIL_FILE_STORE_H_
 
-#include <unistd.h>
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "disallow_copy_and_assign.h"
+#include "platform.h"
 #include "util_common.h"
 
 namespace wvcdm {

libwvdrmengine/cdm/util/include/platform.h

@@ -0,0 +1,33 @@
+// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine Master
+// License Agreement.
+//
+// Platform - Abstracts some utilities between platforms.
+//
+#ifndef WVCDM_UTIL_PLATFORM_H_
+#define WVCDM_UTIL_PLATFORM_H_
+
+#include "util_common.h"
+
+#ifdef _WIN32
+# include <wtypes.h>
+# include <BaseTsd.h>
+# include <winsock2.h>  // For htonl and ntohl.
+# define __PRETTY_FUNCTION__ __FUNCTION__
+# undef NO_ERROR
+# undef GetCurrentTime
+# undef DeleteFile
+
+using ssize_t = SSIZE_T;
+
+inline void sleep(int seconds) {
+  Sleep(seconds * 1000);
+}
+CORE_UTIL_EXPORT int setenv(const char* key, const char* value, int overwrite);
+#else
+# include <arpa/inet.h>
+# include <sys/types.h>
+# include <unistd.h>
+#endif
+
+#endif  // WVCDM_UTIL_PLATFORM_H_

libwvdrmengine/cdm/util/src/platform.cpp

@@ -0,0 +1,21 @@
+// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine Master
+// License Agreement.
+
+#include "platform.h"
+
+#include "stdlib.h"
+
+#ifdef _WIN32
+
+int setenv(const char* key, const char* value, int overwrite) {
+  if (!overwrite) {
+    size_t size;
+    errno_t err = getenv_s(&size, nullptr, 0, key);
+    if (err != 0 || size != 0)
+      return err;  // Return 0 if it exists, but don't change.
+  }
+  return _putenv_s(key, value);
+}
+
+#endif

libwvdrmengine/cdm/util/src/string_conversions.cpp

@@ -4,7 +4,6 @@
 
 #include "string_conversions.h"
 
-#include <arpa/inet.h>
 #include <ctype.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -13,6 +12,7 @@
 #include <vector>
 
 #include "log.h"
+#include "platform.h"
 
 namespace wvcdm {