OEMCrypto Mock SRM functionality

Merge from Widevine repo of http://go/wvgerrit/24730

This CL adds SRM functionality to the modable version of oemcrypto
mock.  This can be used for end-to-end testing.

b/28955873
b/37353534

Change-Id: I2c6f513495ccfd42f7a3d7a3449db6f810563c04

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -157,6 +157,8 @@ TEST_F(OEMCryptoClientTest, CheckSRMCapabilityV13) {
   if (current_result == OEMCrypto_SUCCESS) {
     printf("             Current SRM Version: %d.\n", version);
     EXPECT_NE(OEMCrypto_SUCCESS, OEMCrypto_GetCurrentSRMVersion(NULL));
+  } else if (current_result == OEMCrypto_LOCAL_DISPLAY_ONLY) {
+    printf("             Current SRM Status: Local Display Only.\n");
   } else {
     EXPECT_EQ(OEMCrypto_ERROR_NOT_IMPLEMENTED, current_result);
   }