Handle IPC messages in webContents instead of BrowserWindow.

atom/browser/api/lib/browser-window.coffee

@@ -1,10 +1,32 @@
 EventEmitter = require('events').EventEmitter
 IDWeakMap = require 'id-weak-map'
 app = require 'app'
+ipc = require 'ipc'
 
 BrowserWindow = process.atomBinding('window').BrowserWindow
 BrowserWindow::__proto__ = EventEmitter.prototype
 
+wrapWebContents = (webContents) ->
+  return null unless webContents.isAlive()
+  # webContents is an EventEmitter.
+  webContents.__proto__ = EventEmitter.prototype
+
+  # Wrap around the send method.
+  webContents.send = (args...) ->
+    @_send 'ATOM_INTERNAL_MESSAGE', [args...]
+
+  # Dispatch the ipc messages.
+  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...) =>
+    set = (value) -> event.sendReply JSON.stringify(value)
+    Object.defineProperty event, 'returnValue', {set}
+    Object.defineProperty event, 'sender', value: webContents
+    ipc.emit channel, event, args...
+
+  webContents
+
 # Store all created windows in the weak map.
 BrowserWindow.windows = new IDWeakMap
 
@@ -45,15 +67,10 @@ BrowserWindow::toggleDevTools = ->
   if @isDevToolsOpened() then @closeDevTools() else @openDevTools()
 
 BrowserWindow::getWebContents = ->
-  webContents = @_getWebContents()
-  webContents.__proto__ = EventEmitter.prototype
-  webContents
+  wrapWebContents @_getWebContents()
 
 BrowserWindow::getDevToolsWebContents = ->
-  webContents = @_getDevToolsWebContents()
-  webContents.__proto__ = EventEmitter.prototype
-  webContents = null unless webContents.isAlive()
-  webContents
+  wrapWebContents @_getDevToolsWebContents()
 
 BrowserWindow::restart = ->
   @loadUrl(@getUrl())

atom/browser/api/lib/ipc.coffee

@@ -1,32 +1,3 @@
 EventEmitter = require('events').EventEmitter
-send = process.atomBinding('ipc').send
 
-sendWrap = (channel, processId, routingId, args...) ->
-  BrowserWindow = require 'browser-window'
-  if processId?.constructor is BrowserWindow
-    window = processId
-    args = [routingId, args...]
-    processId = window.getProcessId()
-    routingId = window.getRoutingId()
-
-  send channel, processId, routingId, [args...]
-
-class Ipc extends EventEmitter
-  constructor: ->
-    process.on 'ATOM_INTERNAL_MESSAGE', (args...) =>
-      @emit(args...)
-    process.on 'ATOM_INTERNAL_MESSAGE_SYNC', (channel, event, args...) =>
-      set = (value) -> event.sendReply JSON.stringify(value)
-
-      Object.defineProperty event, 'returnValue', {set}
-      Object.defineProperty event, 'result', {set}
-
-      @emit(channel, event, args...)
-
-  send: (processId, routingId, args...) ->
-    @sendChannel(processId, routingId, 'message', args...)
-
-  sendChannel: (args...) ->
-    sendWrap('ATOM_INTERNAL_MESSAGE', args...)
-
-module.exports = new Ipc
+module.exports = new EventEmitter