[wasm] More extensive indirect dispatch signature mismatch tests.

src/wasm/signature-map.cc

Index: src/wasm/signature-map.cc
diff --git a/src/wasm/signature-map.cc b/src/wasm/signature-map.cc
index e7f8b2fc94d16d66caad53f8778f3e0e7836da24..e7ee4eba4e21361977a0f363990c219e441a2af5 100644
--- a/src/wasm/signature-map.cc
+++ b/src/wasm/signature-map.cc
@@ -8,7 +8,10 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
+SignatureMap::SignatureMap() : mutex_(new base::Mutex()) {}
+
 uint32_t SignatureMap::FindOrInsert(FunctionSig* sig) {
+  base::LockGuard<base::Mutex> guard(mutex_.get());
   auto pos = map_.find(sig);
   if (pos != map_.end()) {
     return pos->second;
@@ -20,6 +23,7 @@ uint32_t SignatureMap::FindOrInsert(FunctionSig* sig) {
 }
 
 int32_t SignatureMap::Find(FunctionSig* sig) const {
+  base::LockGuard<base::Mutex> guard(mutex_.get());
   auto pos = map_.find(sig);
   if (pos != map_.end()) {
     return static_cast<int32_t>(pos->second);