Only turn on UMA WASM metric when synchronous.

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index 06377336c864ba7c91f7aca69f7dcaababb96b9c..a1864c6aa06e32f52b4f9f5573bfd4f642cdc9eb 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -3937,24 +3937,27 @@ Vector<const char> GetDebugName(Zone* zone, wasm::WasmName name, int index) {
 
 WasmCompilationUnit::WasmCompilationUnit(Isolate* isolate,
                                          wasm::ModuleBytesEnv* module_env,
-                                         const wasm::WasmFunction* function)
+                                         const wasm::WasmFunction* function,
+                                         bool is_sync)
     : WasmCompilationUnit(
           isolate, &module_env->module_env,
           wasm::FunctionBody{
               function->sig, module_env->wire_bytes.start(),
               module_env->wire_bytes.start() + function->code_start_offset,
               module_env->wire_bytes.start() + function->code_end_offset},
-          module_env->wire_bytes.GetNameOrNull(function),
-          function->func_index) {}
+          module_env->wire_bytes.GetNameOrNull(function), function->func_index,
+          is_sync) {}
 
 WasmCompilationUnit::WasmCompilationUnit(Isolate* isolate,
                                          wasm::ModuleEnv* module_env,
                                          wasm::FunctionBody body,
-                                         wasm::WasmName name, int index)
+                                         wasm::WasmName name, int index,
+                                         bool is_sync)
     : isolate_(isolate),
       module_env_(module_env),
       func_body_(body),
       func_name_(name),
+      is_sync_(is_sync),
       graph_zone_(new Zone(isolate->allocator(), ZONE_NAME)),
       jsgraph_(new (graph_zone()) JSGraph(
           isolate, new (graph_zone()) Graph(graph_zone()),
@@ -3982,9 +3985,18 @@ void WasmCompilationUnit::InitializeHandles() {
 
 void WasmCompilationUnit::ExecuteCompilation() {
   DCHECK(handles_initialized_);
-  // TODO(ahaas): The counters are not thread-safe at the moment.
-  //    HistogramTimerScope wasm_compile_function_time_scope(
-  //        isolate_->counters()->wasm_compile_function_time());
+  if (is_sync_) {
+    // TODO(karlschimpf): Make this work when asynchronous.
+    // https://bugs.chromium.org/p/v8/issues/detail?id=6361
+    HistogramTimerScope wasm_compile_function_time_scope(
+        isolate_->counters()->wasm_compile_function_time());
+    ExecuteCompilationInternal();
+    return;
+  }
+  ExecuteCompilationInternal();
+}
+
+void WasmCompilationUnit::ExecuteCompilationInternal() {
   if (FLAG_trace_wasm_compiler) {
     if (func_name_.start() != nullptr) {
       PrintF("Compiling WASM function %d:'%.*s'\n\n", func_index(),
@@ -4023,10 +4035,11 @@ void WasmCompilationUnit::ExecuteCompilation() {
       !module_env_->module->is_wasm()));
   ok_ = job_->ExecuteJob() == CompilationJob::SUCCEEDED;
   // TODO(bradnelson): Improve histogram handling of size_t.
-  // TODO(ahaas): The counters are not thread-safe at the moment.
-  //    isolate_->counters()->wasm_compile_function_peak_memory_bytes()
-  // ->AddSample(
-  //        static_cast<int>(jsgraph->graph()->zone()->allocation_size()));
+  if (is_sync_)
+    // TODO(karlschimpf): Make this work when asynchronous.
+    // https://bugs.chromium.org/p/v8/issues/detail?id=6361
+    isolate_->counters()->wasm_compile_function_peak_memory_bytes()->AddSample(
+        static_cast<int>(jsgraph_->graph()->zone()->allocation_size()));
 
   if (FLAG_trace_wasm_decode_time) {
     double pipeline_ms = pipeline_timer.Elapsed().InMillisecondsF();