Register enter/leave fullscreen events in the main process

This will still notify render processes when such events are triggered
without, however, incurring the additional cost of synchronously
retrieving a `BrowserWindow` (and its properties) via `remote` during
startup.

src/application-delegate.coffee

@@ -80,6 +80,12 @@ class ApplicationDelegate
   setWindowFullScreen: (fullScreen=false) ->
     ipcHelpers.call('window-method', 'setFullScreen', fullScreen)
 
+  onDidEnterFullScreen: (callback) ->
+    ipcHelpers.on(ipcRenderer, 'did-enter-full-screen', callback)
+
+  onDidLeaveFullScreen: (callback) ->
+    ipcHelpers.on(ipcRenderer, 'did-leave-full-screen', callback)
+
   openWindowDevTools: ->
     # Defer DevTools interaction to the next tick, because using them during
     # event handling causes some wrong input events to be triggered on

src/main-process/atom-window.coffee

@@ -89,6 +89,12 @@ class AtomWindow
       @emit 'window:loaded'
       @resolveLoadedPromise()
 
+    @browserWindow.on 'enter-full-screen', =>
+      @browserWindow.webContents.send('did-enter-full-screen')
+
+    @browserWindow.on 'leave-full-screen', =>
+      @browserWindow.webContents.send('did-leave-full-screen')
+
     @browserWindow.loadURL url.format
       protocol: 'file'
       pathname: "#{@resourcePath}/static/index.html"

src/window-event-handler.coffee

@@ -20,14 +20,8 @@ class WindowEventHandler
     @subscriptions.add listen(@document, 'click', 'a', @handleLinkClick)
     @subscriptions.add listen(@document, 'submit', 'form', @handleFormSubmit)
 
-    browserWindow = @applicationDelegate.getCurrentWindow()
-    browserWindow.on 'enter-full-screen', @handleEnterFullScreen
-    @subscriptions.add new Disposable =>
-      browserWindow.removeListener('enter-full-screen', @handleEnterFullScreen)
-
-    browserWindow.on 'leave-full-screen', @handleLeaveFullScreen
-    @subscriptions.add new Disposable =>
-      browserWindow.removeListener('leave-full-screen', @handleLeaveFullScreen)
+    @subscriptions.add(@applicationDelegate.onDidEnterFullScreen(@handleEnterFullScreen))
+    @subscriptions.add(@applicationDelegate.onDidLeaveFullScreen(@handleLeaveFullScreen))
 
     @subscriptions.add @atomEnvironment.commands.add @window,
       'window:toggle-full-screen': @handleWindowToggleFullScreen