[fuzzing] add oemcrypto_shrink_usage_table_header_fuzz

Merge from Widevine repo of http://go/wvgerrit/158860

Bug: b/243078947
Test: tested with http://go/ag/20420224

Change-Id: I00d7f96ad86990ed62fb1b81508bf79bbdd3da13

libwvdrmengine/oemcrypto/test/fuzz_tests/oemcrypto_shrink_usage_table_header_fuzz.cc

@@ -0,0 +1,28 @@
+// Copyright 2022 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine
+// License Agreement.
+
+#include "OEMCryptoCENC.h"
+#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(uint32_t)) {
+    return 0;
+  }
+
+  LicenseWithUsageEntryFuzz entry;
+  uint32_t new_entry_count = 0;
+  memcpy(&new_entry_count, data, sizeof(uint32_t));
+  std::vector<uint8_t> header_buffer(size - sizeof(uint32_t));
+  size_t header_buffer_length = header_buffer.size();
+  OEMCrypto_ShrinkUsageTableHeader(new_entry_count, header_buffer.data(),
+                                   &header_buffer_length);
+
+  return 0;
+}
+}  // namespace wvoec