Separate the webContents code in a new file.

atom/browser/api/lib/web-contents.coffee

@@ -0,0 +1,23 @@
+EventEmitter = require('events').EventEmitter
+ipc = require 'ipc'
+
+module.exports.wrap = (webContents) ->
+  return null unless webContents.isAlive()
+
+  # webContents is an EventEmitter.
+  webContents.__proto__ = EventEmitter.prototype
+
+  # Add the send method.
+  webContents.send = (args...) ->
+    @_send 'ATOM_INTERNAL_MESSAGE', [args...]
+
+  # Dispatch IPC messages to the ipc module.
+  webContents.on 'ipc-message', (event, channel, args...) =>
+    Object.defineProperty event, 'sender', value: webContents
+    ipc.emit channel, event, args...
+  webContents.on 'ipc-message-sync', (event, channel, args...) =>
+    Object.defineProperty event, 'returnValue', set: (value) -> event.sendReply JSON.stringify(value)
+    Object.defineProperty event, 'sender', value: webContents
+    ipc.emit channel, event, args...
+
+  webContents