[inspector] perf test for inspector async instrumentation

Prior langing massive async instrumentation refactoring let's add a perf
test to track our progress.

R=dgozman@chromium.org

Bug: v8:7078
Change-Id: I11e1ec962a9f384c2c778061c48935ac410fbe53
Reviewed-on: https://chromium-review.googlesource.com/766647Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49365}

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

@@ -13,6 +13,9 @@
   benchy('Debugger.getPossibleBreakpoints',
     DebuggerGetPossibleBreakpoints,
     SetupGetPossibleBreakpoints);
+  benchy('AsyncStacksInstrumentation',
+    AsyncStacksInstrumentation,
+    SetupAsyncStacksInstrumentation);
 
   function Setup() {
     SendMessage('Debugger.enable');
@@ -57,4 +60,20 @@
       start: {lineNumber: 0, columnNumber: 0, scriptId: scriptId}
     });
   }
+
+  function SetupAsyncStacksInstrumentation() {
+    Setup();
+    SendMessage('Debugger.setAsyncCallStackDepth', {maxDepth: 1024});
+  }
+
+  function AsyncStacksInstrumentation() {
+    var p = Promise.resolve();
+    var nopCallback = () => undefined;
+    var done = false;
+    for (let i = 0; i < 1000; ++i) {
+      p = p.then(nopCallback);
+    }
+    p = p.then(() => done = true);
+    while (!done) %RunMicrotasks();
+  }
 })();

test/js-perf-test/JSTests.json

@@ -602,7 +602,7 @@
       "path": ["Inspector"],
       "main": "run.js",
       "resources": [ "debugger.js", "runtime.js" ],
-      "flags": ["--enable-inspector"],
+      "flags": ["--enable-inspector","--allow-natives-syntax"],
       "results_regexp": "^%s\\-Inspector\\(Score\\): (.+)$",
       "tests": [
         {"name": "Debugger.paused"},