Restart crash service in each spec

spec/static/main.js

@@ -24,7 +24,10 @@ var argv = require('yargs')
   .argv
 
 var window = null
-process.port = 0 // will be used by crash-reporter spec.
+
+ // will be used by crash-reporter spec.
+process.port = 0
+process.crashServicePid = 0
 
 v8.setFlagsFromString('--expose_gc')
 app.commandLine.appendSwitch('js-flags', '--expose_gc')
@@ -329,6 +332,11 @@ ipcMain.on('navigate-with-pending-entry', (event, id) => {
   })
 })
 
+ipcMain.on('crash-service-pid', (event, pid) => {
+  process.crashServicePid = pid
+  event.returnValue = null
+})
+
 // Suspend listeners until the next event and then restore them
 const suspendListeners = (emitter, eventName, callback) => {
   const listeners = emitter.listeners(eventName)