address review comments

src/legacy/core_plugins/kibana/public/dev_tools/render_app.tsx → src/legacy/core_plugins/kibana/public/dev_tools/application.tsx

@@ -29,7 +29,7 @@ import { AppMountContext } from 'kibana/public';
 import { DevTool } from '../../../../../plugins/dev_tools/public';
 
 interface DevToolsWrapperProps {
-  devTools: DevTool[];
+  devTools: readonly DevTool[];
   activeDevTool: DevTool;
   appMountContext: AppMountContext;
   updateRoute: (newRoute: string) => void;
@@ -145,10 +145,10 @@ export function renderApp(
   element: HTMLElement,
   appMountContext: AppMountContext,
   basePath: string,
-  devTools: DevTool[]
+  devTools: readonly DevTool[]
 ) {
   if (redirectOnMissingCapabilities(appMountContext)) {
-    return;
+    return () => {};
   }
   setBadge(appMountContext);
   setBreadcrumbs(appMountContext);

src/legacy/core_plugins/kibana/public/dev_tools/plugin.ts

@@ -36,7 +36,7 @@ export interface DevToolsPluginStartDependencies {
 }
 
 export class DevToolsPlugin implements Plugin {
-  private getSortedDevTools: (() => DevTool[]) | null = null;
+  private getSortedDevTools: (() => readonly DevTool[]) | null = null;
 
   public setup(
     core: CoreSetup,
@@ -49,7 +49,7 @@ export class DevToolsPlugin implements Plugin {
         if (!this.getSortedDevTools) {
           throw new Error('not started yet');
         }
-        const { renderApp } = await import('./render_app');
+        const { renderApp } = await import('./application');
         return renderApp(
           params.element,
           appMountContext,
@@ -60,7 +60,7 @@ export class DevToolsPlugin implements Plugin {
     });
   }
 
-  start(core: CoreStart, { newPlatformDevTools }: DevToolsPluginStartDependencies) {
+  public start(core: CoreStart, { newPlatformDevTools }: DevToolsPluginStartDependencies) {
     this.getSortedDevTools = newPlatformDevTools.getSortedDevTools;
     if (this.getSortedDevTools().length === 0) {
       core.chrome.navLinks.update('kibana:dev_tools', {

src/plugins/dev_tools/README.md

@@ -0,0 +1,29 @@
+# Dev tools plugin
+
+The ui/registry/dev_tools is removed in favor of the `dev_tools` plugin which exposes a register method in the setup contract.
+Registering app works mostly the same as registering apps in core.application.register.
+Routing will be handled by the id of the dev tool - your dev tool will be mounted when the URL matches `/app/kibana#/dev_tools/<YOUR ID>`.
+This API doesn't support angular, for registering angular dev tools, bootstrap a local module on mount into the given HTML element.
+
+During the migration this plugin exposes the registered dev tools in the start contract. This is necessary to keep the dev tools app
+which is still living in the legacy platform working and will be removed once everything is moved over to the new platform. It should
+not be used by other plugins.
+
+## Example registration
+
+```ts
+// For legacy plugins
+import { npSetup } from 'ui/new_platform';
+npSetup.plugins.dev_tools.register(/* same details here */);
+
+// For new plugins: first add 'dev_tools' to the list of `optionalPlugins` 
+// in your kibana.json file. Then access the plugin directly in `setup`:
+
+class MyPlugin {
+  setup(core, plugins) {
+    if (plugins.dev_tools) {
+      plugins.dev_tools.register(/* same details here. */);
+    }
+  }
+}
+```

src/plugins/dev_tools/public/plugin.ts

@@ -43,7 +43,7 @@ export interface DevToolsStart {
    * becomes an implementation detail.
    * @deprecated
    */
-  getSortedDevTools: () => DevTool[];
+  getSortedDevTools: () => readonly DevTool[];
 }
 
 /**
@@ -87,21 +87,27 @@ export interface DevTool {
 }
 
 export class DevToolsPlugin implements Plugin<DevToolsSetup, DevToolsStart> {
-  private devTools: DevTool[] = [];
+  private readonly devTools = new Map<string, DevTool>();
 
-  private getSortedDevTools() {
-    return sortBy(this.devTools, 'order');
+  private getSortedDevTools(): readonly DevTool[] {
+    return sortBy([...this.devTools.values()], 'order');
   }
 
   public setup(core: CoreSetup) {
     return {
       register: (devTool: DevTool) => {
-        this.devTools.push(devTool);
+        if (this.devTools.has(devTool.id)) {
+          throw new Error(
+            `Dev tool with id [${devTool.id}] has already been registered. Use a unique id.`
+          );
+        }
+
+        this.devTools.set(devTool.id, devTool);
       },
     };
   }
 
-  start() {
+  public start() {
     return {
       getSortedDevTools: this.getSortedDevTools.bind(this),
     };