Make sure webContents is created when opening devtools.

Fixes atom/atom#2270.

atom/browser/api/atom_api_window.cc

@@ -362,7 +362,7 @@ void Window::BuildPrototype(v8::Isolate* isolate,
       .SetMethod("flashFrame", &Window::FlashFrame)
       .SetMethod("setKiosk", &Window::SetKiosk)
       .SetMethod("isKiosk", &Window::IsKiosk)
-      .SetMethod("openDevTools", &Window::OpenDevTools)
+      .SetMethod("_openDevTools", &Window::OpenDevTools)
       .SetMethod("closeDevTools", &Window::CloseDevTools)
       .SetMethod("isDevToolsOpened", &Window::IsDevToolsOpened)
       .SetMethod("inspectElement", &Window::InspectElement)

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

@@ -18,17 +18,6 @@ BrowserWindow::_init = ->
   @webContents = @getWebContents()
   @webContents.once 'destroyed', => @webContents = null
 
-  # Define getter for devToolsWebContents.
-  devToolsWebContents = null
-  @__defineGetter__ 'devToolsWebContents', ->
-    if @isDevToolsOpened()
-      # Get a new devToolsWebContents if previous one has been destroyed, it
-      # could happen when the devtools has been closed and then reopened.
-      devToolsWebContents = null unless devToolsWebContents?.isAlive()
-      devToolsWebContents ?= @getDevToolsWebContents()
-    else
-      devToolsWebContents = null
-
   # Remember the window.
   id = BrowserWindow.windows.add this
 
@@ -37,10 +26,12 @@ BrowserWindow::_init = ->
   @once 'closed', ->
     BrowserWindow.windows.remove id if BrowserWindow.windows.has id
 
-  # Tell the rpc server that a render view has been deleted and we need to
-  # release all objects owned by it.
-  @webContents.on 'render-view-deleted', (event, processId, routingId) ->
-    process.emit 'ATOM_BROWSER_RELEASE_RENDER_VIEW', "#{processId}-#{routingId}"
+BrowserWindow::openDevTools = ->
+  @_openDevTools()
+
+  # Force devToolsWebContents to be created.
+  @devToolsWebContents = @getDevToolsWebContents()
+  @devToolsWebContents.once 'destroyed', => @devToolsWebContents = null
 
 BrowserWindow::toggleDevTools = ->
   if @isDevToolsOpened() then @closeDevTools() else @openDevTools()

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

@@ -15,6 +15,11 @@ module.exports.wrap = (webContents) ->
   webContents.getId = -> "#{@getProcessId()}-#{@getRoutingId()}"
   webContents.equal = (other) -> @getId() is other.getId()
 
+  # Tell the rpc server that a render view has been deleted and we need to
+  # release all objects owned by it.
+  webContents.on 'render-view-deleted', (event, processId, routingId) ->
+    process.emit 'ATOM_BROWSER_RELEASE_RENDER_VIEW', "#{processId}-#{routingId}"
+
   # Dispatch IPC messages to the ipc module.
   webContents.on 'ipc-message', (event, channel, args...) =>
     Object.defineProperty event, 'sender', value: webContents