Preserve command line flags when restarting

This performs restarts in the main process and uses ipc to request restarts from application windows. We preserve the following settings:

* dev mode
* custom resource path
* safe mode
* portable mode
* socket path
* log file path
* user data dir

src/application-delegate.coffee

@@ -58,8 +58,7 @@ class ApplicationDelegate
     ipcRenderer.send("call-window-method", "reload")
 
   restartApplication: ->
-    remote.app.relaunch({args: []})
-    remote.app.quit()
+    ipcRenderer.send("restart-application")
 
   minimizeWindow: ->
     ipcRenderer.send("call-window-method", "minimize")

src/main-process/atom-application.coffee

@@ -62,7 +62,7 @@ class AtomApplication
   exit: (status) -> app.exit(status)
 
   constructor: (options) ->
-    {@resourcePath, @devResourcePath, @version, @devMode, @safeMode, @socketPath, timeout, clearWindowState} = options
+    {@resourcePath, @devResourcePath, @version, @devMode, @safeMode, @socketPath, @logFile, @setPortable, @userDataDir, timeout, clearWindowState} = options
     @socketPath = null if options.test
     @pidsToOpenWindows = {}
     @windows = []
@@ -254,6 +254,9 @@ class AtomApplication
       event?.preventDefault()
       @emit('application:new-window')
 
+    @disposable.add ipcHelpers.on ipcMain, 'restart-application', =>
+      @restart()
+
     # A request from the associated render process to open a new render process.
     @disposable.add ipcHelpers.on ipcMain, 'open', (event, options) =>
       window = @windowForEvent(event)
@@ -738,5 +741,17 @@ class AtomApplication
       message: "You will need to restart Atom for this change to take effect."
       buttons: ['Restart Atom', 'Cancel']
     if chosen is 0
-      app.relaunch({args: []})
-      app.quit()
+      @restart()
+
+  restart: ->
+    args = []
+    args.push("--safe") if @safeMode
+    args.push("--portable") if @setPortable
+    args.push("--log-file=#{@logFile}") if @logFile?
+    args.push("--socket-path=#{@socketPath}") if @socketPath?
+    args.push("--user-data-dir=#{@userDataDir}") if @userDataDir?
+    if @devMode
+      args.push('--dev')
+      args.push("--resource-path=#{@resourcePath}")
+    app.relaunch({args})
+    app.quit()