DevTools: Implement a reliable check for isNodeJS()

The isNodeJS() method validates whether target
has only SDK.Target.Capability.JS set. This
patch makes it more explicit and resolves the
existing TODO in the isNodeJS() method.

The creator of the target must now explicitly
mark the target as Node.js by calling
markAsNodeJS() on the target object, thus
avoiding the dependency on SDK.Target.Capability.JS.

Change-Id: I4da9af58ddc42eba2b6b91f7b1b81b411180256b
Reviewed-on: https://chromium-review.googlesource.com/1116761
Commit-Queue: Andrey Lushnikov <lushnikov@chromium.org>
Reviewed-by: Andrey Lushnikov <lushnikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572375}

third_party/WebKit/LayoutTests/http/tests/devtools/persistence/persistence-sync-content-nodejs.js

@@ -9,7 +9,7 @@
 
   var testMapping = BindingsTestRunner.initializeTestMapping();
   // Pretend we are running under V8 front-end.
-  SDK.targetManager.mainTarget().setIsNodeJSForTest();
+  SDK.targetManager.mainTarget().markAsNodeJS();
 
   var content = ['', '', 'var express = require("express");', '//TODO'].join('\n');
 

third_party/WebKit/LayoutTests/http/tests/devtools/sources/debugger-breakpoints/nodejs-set-breakpoint.js

@@ -8,7 +8,7 @@
   await TestRunner.loadModule('sdk_test_runner');
   await TestRunner.showPanel('sources');
 
-  SDK.targetManager.mainTarget().setIsNodeJSForTest();
+  SDK.targetManager.mainTarget().markAsNodeJS();
   SourcesTestRunner.startDebuggerTest();
 
   var debuggerModel = SDK.targetManager.mainTarget().model(SDK.DebuggerModel);

third_party/blink/renderer/devtools/front_end/inspector_main/InspectorMain.js

@@ -34,6 +34,8 @@ InspectorMain.InspectorMain = class extends Common.Object {
     const target = SDK.targetManager.createTarget(
         'main', Common.UIString('Main'), this._capabilitiesForMainTarget(), this._createMainConnection.bind(this),
         null);
+    if (Runtime.queryParam('v8only'))
+      target.markAsNodeJS();
     target.runtimeAgent().runIfWaitingForDebugger();
   }
 

third_party/blink/renderer/devtools/front_end/js_main/JsMain.js

@@ -13,6 +13,7 @@ JsMain.JsMain = class extends Common.Object {
     Host.userMetrics.actionTaken(Host.UserMetrics.Action.ConnectToNodeJSDirectly);
     const target = SDK.targetManager.createTarget(
         'main', Common.UIString('Main'), SDK.Target.Capability.JS, this._createMainConnection.bind(this), null);
+    target.markAsNodeJS();
     target.runtimeAgent().runIfWaitingForDebugger();
     InspectorFrontendHost.connectionReady();
   }

third_party/blink/renderer/devtools/front_end/node_main/NodeMain.js

@@ -100,6 +100,7 @@ NodeMain.NodeChildTargetManager = class extends SDK.SDKModel {
     const target = this._targetManager.createTarget(
         targetInfo.targetId, Common.UIString('Node.js: %s', targetInfo.url), SDK.Target.Capability.JS,
         this._createChildConnection.bind(this, this._targetAgent, sessionId), this._parentTarget);
+    target.markAsNodeJS();
     target.runtimeAgent().runIfWaitingForDebugger();
   }
 

third_party/blink/renderer/devtools/front_end/sdk/Target.js

@@ -46,12 +46,11 @@ SDK.Target = class extends Protocol.TargetBase {
    * @return {boolean}
    */
   isNodeJS() {
-    // TODO(lushnikov): this is an unreliable way to detect Node.js targets.
-    return this._capabilitiesMask === SDK.Target.Capability.JS || this._isNodeJSForTest;
+    return this._isNodeJS;
   }
 
-  setIsNodeJSForTest() {
-    this._isNodeJSForTest = true;
+  markAsNodeJS() {
+    this._isNodeJS = true;
   }
 
   /**