Clean up fuzz helper classes

- Remove OEMCrypto state changes hidden in constructors and destructors.
- Use composition instead of inheritance to structure classes.
- Avoid calling non-trivial destructors for objects with static
  lifetime.

Merged from https://widevine-internal-review.googlesource.com/168497
Merged from https://widevine-internal-review.googlesource.com/171170
Merged from https://widevine-internal-review.googlesource.com/171171
Merged from https://widevine-internal-review.googlesource.com/171870

Change-Id: I20476a7b1132d11f011b8650ec01e3c2dc3fc0e8

libwvdrmengine/oemcrypto/test/fuzz_tests/oemcrypto_load_provisioning_fuzz.cc

@@ -4,17 +4,16 @@
 
 #include "oemcrypto_fuzz_helper.h"
 
-namespace wvoec {
-
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  // Redirect printf and log statements from oemcrypto functions to a file to
-  // reduce noise
-  RedirectStdoutToFile();
-  if (size < sizeof(ODK_ParsedProvisioning) + sizeof(RSAPrivateKeyMessage)) {
+  wvoec::RedirectStdoutToFile();
+
+  if (size <
+      sizeof(ODK_ParsedProvisioning) + sizeof(wvoec::RSAPrivateKeyMessage)) {
     return 0;
   }
 
-  OEMCryptoProvisioningAPIFuzz provisioning_api_fuzz;
+  wvoec::OEMCryptoProvisioningAPIFuzz provisioning_api_fuzz;
+  provisioning_api_fuzz.Intialize();
   provisioning_api_fuzz.provisioning_messages().SignAndVerifyRequest();
   // Interpreting input fuzz data as unencrypted(core_response + provisioning
   // message data) from provisioning server.
@@ -22,6 +21,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
                                                                          size);
   provisioning_api_fuzz.provisioning_messages().EncryptAndSignResponse();
   provisioning_api_fuzz.provisioning_messages().LoadResponse();
+  provisioning_api_fuzz.Terminate();
   return 0;
 }
-}  // namespace wvoec