Improve OEMCrypto unit tests

This is a merge of http://go/wvgerrit/13701 and http://go/wvgerrit/13780.

I added a new set of engine properties for the mock oemcrypto.  This
set pretends to be level 1. This allows the widevine build bot to test
the dual security level path: a level 1 liboemcrypto.so and a fall
back to L3.

I also adjusted the failing test in oemcrypto_test.cpp.  A correct fix
requires us to rewrite some of the oemcrypto mock code so that it
returns real error codes instead of just 'false' on error.

Change-Id: I9cdbfc23c87ad2fb6068eac1394ce4c5b6a32dae

libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_device_properties_L1.cpp

@@ -0,0 +1,49 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+//  Mock implementation of OEMCrypto APIs
+//
+//  This file contains oemcrypto engine properties that would be for a
+//  level 1 device.
+#include "oemcrypto_engine_mock.h"
+
+namespace wvoec_mock {
+
+// If local_display() returns true, we pretend we are using a built-in display,
+// instead of HDMI or WiFi output.
+bool CryptoEngine::local_display() {
+  return true;
+}
+
+// A closed platform is permitted to use clear buffers.
+bool CryptoEngine::closed_platform() {
+  return false;
+}
+
+// Returns the HDCP version currently in use.
+OEMCrypto_HDCP_Capability CryptoEngine::current_hdcp_capability() {
+  return local_display() ? HDCP_NO_DIGITAL_OUTPUT : HDCP_V1;
+}
+
+// Returns the max HDCP version supported.
+OEMCrypto_HDCP_Capability CryptoEngine::maximum_hdcp_capability() {
+  return HDCP_NO_DIGITAL_OUTPUT;
+}
+
+// Returns true if the client supports persistent storage of
+// offline usage table information.
+bool CryptoEngine::supports_storage() {
+  return true;
+}
+
+// Returns true to indicate the client does support anti-rollback hardware.
+bool CryptoEngine::is_anti_rollback_hw_present() {
+  return true;
+}
+
+// Returns "L3" for a software only library.  L1 is for hardware protected
+// data paths.
+const char* CryptoEngine::security_level() {
+  return "L1";
+}
+
+}  // namespace wvoec_mock