Eliminate errors from calling ChromeLauncher.kill() twice (GoogleChro…

…me#1131)

lighthouse-cli/chrome-launcher.ts

@@ -219,6 +219,7 @@ class ChromeLauncher {
         if (process.platform === 'win32') {
           spawnSync(`taskkill /pid ${this.chrome.pid} /T /F`);
         }
+        this.chrome = null;
       } else {
         // fail silently as we did not start chrome
         resolve();
@@ -227,24 +228,24 @@ class ChromeLauncher {
   }
 
   destroyTmp(): Promise<undefined> {
-    if (!this.TMP_PROFILE_DIR) {
-      return Promise.resolve();
-    }
+    return new Promise(resolve => {
+      if (!this.TMP_PROFILE_DIR) {
+        return resolve();
+      }
 
-    log.verbose('ChromeLauncher', `Removing ${this.TMP_PROFILE_DIR}`);
+      log.verbose('ChromeLauncher', `Removing ${this.TMP_PROFILE_DIR}`);
 
-    if (this.outFile) {
-      fs.closeSync(this.outFile);
-    }
+      if (this.outFile) {
+        fs.closeSync(this.outFile);
+        this.outFile = null;
+      }
 
-    if (this.errFile) {
-      fs.closeSync(this.errFile);
-    }
+      if (this.errFile) {
+        fs.closeSync(this.errFile);
+        this.errFile = null;
+      }
 
-    return new Promise((resolve) => {
-      rimraf(this.TMP_PROFILE_DIR, function() {
-        resolve();
-      });
+      rimraf(this.TMP_PROFILE_DIR, () => resolve());
     });
   }
 };

lighthouse-cli/test/cli/chrome-launcher-test.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright 2016 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+require('../../compiled-check.js')('chrome-launcher.js');
+
+const ChromeLauncher = require('../../chrome-launcher.js').ChromeLauncher;
+
+/* eslint-env mocha */
+
+describe('ChromeLauncher', () => {
+  it('doesn\'t fail when killed twice', () => {
+    const chromeInstance = new ChromeLauncher();
+    return chromeInstance.run()
+      .then(() => {
+        return Promise.all([
+          chromeInstance.kill(),
+          chromeInstance.kill()
+        ]);
+      });
+  });
+});