Don’t bundle DebugTool in production

[gaearon]

Most of this diff is indentation.

I am removing all __DEV__ checks from ReactDebugTool and ReactDOMDebugTool code. Instead, I am conditionally requiring them—in production, ReactInstrumentation.debugTool and ReactDOMInstrumentation.debugTool would now be null after this change.

Why I am doing this:

1. Debug tools are not currently used in production at all. All calls to .debugTool.* are guarded by __DEV__.
2. When we add a __PROFILE__ build, we can change the same condition to include __PROFILE__. There’s nothing here that would make it harder in the future.
3. We are currently bundling unnecessary noops with method names and strings in production, and as we add more events, they will keep growing:

In the future, we might allow attaching devtools in production. Let’s do it when we actually have a use case for it. Right now it’s weird because we have these constraints that don’t actually end up getting used. This makes debug tool architecture more confusing to whoever who will be adding the __PROFILE__ build.

Even when we allow this, it is likely that the actual DebugTool would be external code. There is no need for it to live inside React. The default “broadcasting” DebugTools are good for development but I don’t see why they are useful in prod.

Let’s just keep it simple for now and let the code reflect our real usage. Debug tools are only called in development environment now.

This reduces build size a bit:

     =      = build/react-dom-server.js                                        
     =      = build/react-dom-server.min.js                                    
     =      = build/react-dom.js                                               
     =      = build/react-dom.min.js                                           
  -471     -4 build/react-with-addons.js                                       
 -2732   -620 build/react-with-addons.min.js                                   
  -471     -9 build/react.js                                                   
 -2733   -583 build/react.min.js 

If we are concerned about stray .debugTool.* calls that would blow up in production, we can lint against using .debugTool. outside a __DEV__ block. We don’t add new calls very often though so I’m not sure if it’s worth it.