Fix UMA stat for collecting function decoding time.

This fixes collection of function decoding time (See comment #20 of
v8:6361). Updated other path for decoding to also update UMA stat.

Bug: v8:6361
Change-Id: I8e6cb398aebd7847e064d3b9a979586ded118513
Reviewed-on: https://chromium-review.googlesource.com/598458
Commit-Queue: Karl Schimpf <kschimpf@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47136}

src/wasm/module-compiler.cc

@@ -308,12 +308,18 @@ void ModuleCompiler::ValidateSequentially(ModuleBytesEnv* module_env,
   for (uint32_t i = 0; i < module->functions.size(); ++i) {
     const WasmFunction& func = module->functions[i];
     if (func.imported) continue;
-
     const byte* base = module_env->wire_bytes.start();
     FunctionBody body{func.sig, func.code.offset(), base + func.code.offset(),
                       base + func.code.end_offset()};
-    DecodeResult result = VerifyWasmCode(isolate_->allocator(),
+    DecodeResult result;
+    {
+      auto time_counter = module->is_wasm()
+                              ? counters()->wasm_decode_wasm_function_time()
+                              : counters()->wasm_decode_asm_function_time();
+      TimedHistogramScope wasm_decode_function_time_scope(time_counter);
+      result = VerifyWasmCode(isolate_->allocator(),
                               module_env->module_env.module, body);
+    }
     if (result.failed()) {
       WasmName str = module_env->wire_bytes.GetName(&func);
       thrower->CompileError("Compiling function #%d:%.*s failed: %s @+%u", i,

src/wasm/module-decoder.cc

@@ -1004,11 +1004,6 @@ class ModuleDecoder : public Decoder {
   // Verifies the body (code) of a given function.
   void VerifyFunctionBody(AccountingAllocator* allocator, uint32_t func_num,
                           ModuleBytesEnv* menv, WasmFunction* function) {
-    auto time_counter = IsWasm()
-                            ? GetCounters()->wasm_decode_wasm_function_time()
-                            : GetCounters()->wasm_decode_asm_function_time();
-    TimedHistogramScope wasm_decode_function_time_scope(time_counter);
-
     WasmFunctionName func_name(function,
                                menv->wire_bytes.GetNameOrNull(function));
     if (FLAG_trace_wasm_decoder || FLAG_trace_wasm_decode_time) {
@@ -1019,8 +1014,15 @@ class ModuleDecoder : public Decoder {
         function->sig, function->code.offset(),
         start_ + GetBufferRelativeOffset(function->code.offset()),
         start_ + GetBufferRelativeOffset(function->code.end_offset())};
-    DecodeResult result = VerifyWasmCode(
+    DecodeResult result;
+    {
+      auto time_counter = IsWasm()
+                              ? GetCounters()->wasm_decode_wasm_function_time()
+                              : GetCounters()->wasm_decode_asm_function_time();
+      TimedHistogramScope wasm_decode_function_time_scope(time_counter);
+      result = VerifyWasmCode(
           allocator, menv == nullptr ? nullptr : menv->module_env.module, body);
+    }
     if (result.failed()) {
       // Wrap the error message from the function decoder.
       std::ostringstream wrapped;