Allow selective removal of Usage Table Entries by PST

This is a merge of http://go/wvgerrit/13693 in the Widevine
repository.

This adds level 3 and mock implementation and unit tests for the
OEMCrypto function OEMCrypto_ForceDeleteUsageEntry.  It also plumbs
this function up into CdmEngine, CdmSession, and CryptoSession so that
deleting all usage information for a given app id will now delete the
entries in OEMCrypto, too.

b/18194071

Change-Id: Iaea4034a507b323878657215784edfe95876386a

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -1522,6 +1522,12 @@ class Session {
                                          &signature_[0], signature_.size()));
   }
 
+  void ForceDeleteEntry(const std::string& pst) {
+    ASSERT_EQ(OEMCrypto_SUCCESS,
+              OEMCrypto_ForceDeleteUsageEntry(
+                  reinterpret_cast<const uint8_t *>(pst.c_str()), pst.length()));
+  }
+
   MessageData& license() { return license_; }
   MessageData& encrypted_license() { return encrypted_license_; }
   const uint8_t* message_ptr() {
@@ -4877,6 +4883,32 @@ TEST_P(DISABLED_UsageTableTest, DeleteActiveEntry) {
   }
 }
 
+TEST_P(DISABLED_UsageTableTest, ForceDeleteActiveEntry) {
+  if (OEMCrypto_SupportsUsageTable()) {
+    ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_UpdateUsageTable());
+    Session s;
+    s.open();
+    s.GenerateDerivedKeys();
+    std::string pst = "my pst";
+    s.FillSimpleMessage(
+        0, wvoec_mock::kControlNonceEnabled | wvoec_mock::kControlNonceRequired,
+        s.get_nonce(), pst);
+    s.EncryptAndSign();
+    s.LoadTestKeys(pst, new_mac_keys_);
+    s.TestDecryptCTR();
+    s.GenerateReport(pst);
+    s.close();
+
+    s.ForceDeleteEntry(pst);
+
+    // Now that session is deleted, we can't generate a report for it.
+    Session s3;
+    s3.open();
+    s3.GenerateReport(pst, false);
+    s3.close();
+  }
+}
+
 TEST_P(DISABLED_UsageTableTest, DeleteInactiveEntry) {
   if (OEMCrypto_SupportsUsageTable()) {
     ASSERT_EQ(OEMCrypto_SUCCESS, OEMCrypto_UpdateUsageTable());