Refactor oemcrypto mock into stand alone reference code

Merge from Widevine repo of http://go/wvgerrit/46204
Refactor utility code - split the mock, step 1

Merge from Widevine repo of http://go/wvgerrit/46205
Move some OEMCrypto types to common header - split the mock, step 2

Merge from Widevine repo of http://go/wvgerrit/46206
Split mock into two -- step 3

Merge from Widevine repo of http://go/wvgerrit/47460
Split the mock into two -- step 3.5

The CL moves several files used by oemcrypto and cdm into a common
subdirectory, so that it may more easily be shared with partners.

The CORE_DISALLOW_COPY_AND_ASSIGN macro was moved to its own header in
the util/include directory.

This CL removes some references to the mock from other code, and puts
some constants and types, such as the definition of the keybox, into a
header in oemcrypto.

Test: tested as part of http://go/ag/4674759
bug: 76393338
Change-Id: I75b4bde7062ed8ee572c97ebc2f4da018f4be0c9

libwvdrmengine/cdm/util/src/clock.cpp

@@ -0,0 +1,20 @@
+// 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.
+//
+// Clock - implemented using the standard linux time library
+
+#include "clock.h"
+
+#include <sys/time.h>
+
+namespace wvcdm {
+
+int64_t Clock::GetCurrentTime() {
+  struct timeval tv;
+  tv.tv_sec = tv.tv_usec = 0;
+  gettimeofday(&tv, NULL);
+  return tv.tv_sec;
+}
+
+}  // namespace wvcdm