Initial outline for new devtools api

src/renderers/dom/ReactDOM.js

@@ -14,6 +14,7 @@
 'use strict';
 
 var ReactDOMComponentTree = require('ReactDOMComponentTree');
+var ReactDOMDevtools = require('ReactDOMDevtools');
 var ReactDefaultInjection = require('ReactDefaultInjection');
 var ReactMount = require('ReactMount');
 var ReactPerf = require('ReactPerf');
@@ -35,6 +36,8 @@ var React = {
   render: render,
   unmountComponentAtNode: ReactMount.unmountComponentAtNode,
   version: ReactVersion,
+  addDevtool: addDevtool,
+  removeDevtool: removeDevtool,
 
   /* eslint-disable camelcase */
   unstable_batchedUpdates: ReactUpdates.batchedUpdates,

src/renderers/dom/shared/ReactDOMDevtools.js

@@ -0,0 +1,52 @@
+/**
+ * Copyright 2013-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule ReactDOMDevtools
+ */
+
+'use strict';
+
+var warning = require('warning');
+
+var eventHandlers = [];
+var handlerDoesThrowForEvent = {};
+
+var ReactDOMDevtools = {
+  addDevtool(devtool) {
+    eventHandlers.push(devtool);
+  },
+
+  removeDevtool(devtool) {
+    for (var i = 0; i < eventHandlers.length; i++) {
+      if (eventHandlers[i] === devtool) {
+        eventHandlers.splice(i, 1);
+        i--;
+      }
+    }
+  },
+
+  emitEvent(eventName, eventData) {
+    if (__DEV__) {
+      eventHandlers.forEach(function(handler) {
+        try {
+          handler.handleEvent(eventName, eventData);
+        } catch (e) {
+          warning(
+            !handlerDoesThrowForEvent[eventName],
+            'exception thrown by devtool while handling %s: %s',
+            eventName,
+            e.message
+          );
+          handlerDoesThrowForEvent[eventName] = true;
+        }
+      });
+    }
+  },
+};
+
+module.exports = ReactDOMDevtools;