[wasm] Use a Managed<WasmModule> to hold metadata about modules.

test/fuzzer/wasm-section-fuzzers.cc

Index: test/fuzzer/wasm-section-fuzzers.cc
diff --git a/test/fuzzer/wasm-section-fuzzers.cc b/test/fuzzer/wasm-section-fuzzers.cc
index e95beba0fdb42a27332b9df92bef769b3aac03b7..13dbb199aa64dd362e6014fc7223f22d0384bf31 100644
--- a/test/fuzzer/wasm-section-fuzzers.cc
+++ b/test/fuzzer/wasm-section-fuzzers.cc
@@ -57,7 +57,7 @@ int fuzz_wasm_section(WasmSectionCode section, const uint8_t* data,
   ErrorThrower thrower(i_isolate, "decoder");
 
   std::unique_ptr<const WasmModule> module(testing::DecodeWasmModuleForTesting(
-      i_isolate, &zone, &thrower, buffer.begin(), buffer.end(), kWasmOrigin));
+      i_isolate, &thrower, buffer.begin(), buffer.end(), kWasmOrigin));
 
   return 0;
 }