Add js-perf-test to exercise v8_inspector::String16

BUG=chromium:738469

Review-Url: https://codereview.chromium.org/2962213002
Cr-Commit-Position: refs/heads/master@{#46612}

test/js-perf-test/Inspector/debugger.js

@@ -2,23 +2,24 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-new BenchmarkSuite('Debugger.paused', [10000], [
-  new Benchmark('Debugger.paused', false, false, 0, DebuggerPaused, DebuggerEnable, DebuggerDisable),
-]);
+(function() {
+  new BenchmarkSuite('Debugger.paused', [10000], [
+    new Benchmark('Debugger.paused', false, false, 0, DebuggerPaused, Setup, TearDown),
+  ]);
 
-let lastId = 0;
-function DebuggerEnable() {
-  send(JSON.stringify({id: ++lastId, method: 'Debugger.enable'}));
-  // force lazy compilation of inspector related scrtips
-  send(JSON.stringify({id: ++lastId, method: 'Runtime.evaluate', params: {expression: ''}}));
-}
+  function Setup() {
+    SendMessage('Debugger.enable');
+    // Force lazy compilation of inspector related scripts.
+    SendMessage('Runtime.evaluate', {expression: ''});
+  }
 
-function DebuggerDisable() {
-  send(JSON.stringify({id: ++lastId, method: 'Debugger.disable'}));
-}
+  function TearDown() {
+    SendMessage('Debugger.disable');
+  }
 
-function DebuggerPaused() {
+  function DebuggerPaused() {
     for (var i = 0; i < 10; ++i) {
       debugger;
     }
-}
+  }
+})();

test/js-perf-test/Inspector/run.js

@@ -5,8 +5,10 @@
 load('../base.js');
 
 load('debugger.js');
+load('runtime.js');
 
-var success = true;
+let success = true;
+let lastId = 0;
 
 function PrintResult(name, result) {
   print(name + '-Inspector(Score): ' + result);
@@ -26,3 +28,11 @@ BenchmarkSuite.config.doDeterministic = undefined;
 BenchmarkSuite.RunSuites({ NotifyResult: PrintResult,
                            NotifyError: PrintError,
                            NotifyStep: PrintStep });
+
+function SendMessage(method, params) {
+  let obj = {id: ++lastId, method: method};
+  if (params) {
+    obj.params = params;
+  }
+  send(JSON.stringify(obj));
+}

test/js-perf-test/Inspector/runtime.js

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+(function() {
+  new BenchmarkSuite('Runtime.evaluate(String16Cstor)', [1000], [
+    new Benchmark('Runtime.evaluate(String16Cstor)', false, false, 0, EvaluateTest, Setup, TearDown),
+  ]);
+
+  function Setup() {
+    // Force lazy compilation of inspector related scripts.
+    SendMessage('Runtime.evaluate', {expression: ''});
+  }
+
+  function TearDown() {
+  }
+
+  function EvaluateTest() {
+    // This is meant to exercise the overhead of v8_inspector::String16
+    // constructors. https://crbug.com/738469
+    for (var i = 0; i < 10; ++i) {
+      SendMessage('Runtime.evaluate', {expression: '({})', returnByValue: true});
+    }
+  }
+})();

test/js-perf-test/JSTests.json

@@ -550,11 +550,12 @@
       "name": "Inspector",
       "path": ["Inspector"],
       "main": "run.js",
-      "resources": [ "debugger.js" ],
+      "resources": [ "debugger.js", "runtime.js" ],
       "flags": ["--enable-inspector"],
       "results_regexp": "^%s\\-Inspector\\(Score\\): (.+)$",
       "tests": [
-        {"name": "Debugger.paused"}
+        {"name": "Debugger.paused"},
+        {"name": "Runtime.evaluate(String16Cstor)"}
       ]
     }
   ]