Fix launching chrome on windows

  related issue #749

packages/devtools-launchpad/src/server/launch.js

@@ -6,6 +6,7 @@ const ps = require("child_process");
 const path = require("path");
 const { isFirefoxRunning } = require("./utils/firefox");
 const firefoxDriver = require("../../bin/firefox-driver");
+const isWindows = /^win/.test(process.platform);
 const {
   getValue
 } = require("devtools-config");
@@ -23,6 +24,13 @@ function handleLaunchRequest(req, res) {
         tcpPort: getValue("firefox.tcpPort")
       };
       if (!isRunning) {
+        process.on('unhandledRejection', (err)=> {
+          if (err.message.indexOf('Could not locate Firefox on the current system')>-1) {
+            console.error('selenium-webdriver could not locate Firefox, please launch it manually.');
+          } else {
+            throw err;
+          }
+        });
         firefoxDriver.start(location, options);
         res.end("launched firefox");
       } else {
@@ -32,8 +40,12 @@ function handleLaunchRequest(req, res) {
   }
 
   if (browser == "Chrome") {
-    ps.spawn(path.resolve(__dirname, "../../bin/chrome-driver.js"),
-     ["--location", location]);
+    const chromeDriver= path.resolve(__dirname, "../../bin/chrome-driver.js");
+    if (isWindows) {
+      ps.spawn('node', [chromeDriver, "--location", location]);
+    } else {
+      ps.spawn(chromeDriver, ["--location", location]);
+    }
     res.end("launched chrome");
   }
 }