Move plugin choice from explorer to homepage (#979)

The explorer no longer ships with a set of default plugins. (This made
an inappropriate dependency from explorer/ to plugins/, and complicated
explorer's contract as a generic component.) Instead, the homepage
module is responsible for choosing the plugins to display on the
homepage.

Test plan: `yarn test --full` passes, and `yarn start` reveals a
functioning homepage and prototype.

src/explorer/App.js

@@ -8,7 +8,6 @@ import CheckedLocalStore from "../webutil/checkedLocalStore";
 import BrowserLocalStore from "../webutil/browserLocalStore";
 import Link from "../webutil/Link";
 
-import {defaultStaticAdapters} from "./adapters/defaultPlugins";
 import {PagerankTable} from "./pagerankTable/Table";
 import type {WeightedTypes} from "../analysis/weights";
 import {defaultWeightsForAdapterSet} from "./weights/weights";
@@ -22,7 +21,10 @@ import {
 } from "./state";
 import {StaticAdapterSet} from "./adapters/adapterSet";
 
-export default class AppPage extends React.Component<{|+assets: Assets|}> {
+export class AppPage extends React.Component<{|
+  +assets: Assets,
+  +adapters: StaticAdapterSet,
+|}> {
   static _LOCAL_STORE = new CheckedLocalStore(
     new BrowserLocalStore({
       version: "2",
@@ -35,7 +37,7 @@ export default class AppPage extends React.Component<{|+assets: Assets|}> {
     return (
       <App
         assets={this.props.assets}
-        adapters={defaultStaticAdapters()}
+        adapters={this.props.adapters}
         localStore={AppPage._LOCAL_STORE}
       />
     );

src/explorer/adapters/defaultPlugins.js

@@ -1,13 +0,0 @@
-// @flow
-
-import {StaticAdapterSet} from "./adapterSet";
-import {StaticAppAdapter as GithubAdapter} from "../../plugins/github/appAdapter";
-import {StaticAppAdapter as GitAdapter} from "../../plugins/git/appAdapter";
-import {GithubGitGateway} from "../../plugins/github/githubGitGateway";
-
-export function defaultStaticAdapters(): StaticAdapterSet {
-  return new StaticAdapterSet([
-    new GithubAdapter(),
-    new GitAdapter(new GithubGitGateway()),
-  ]);
-}

src/homepage/homepageExplorer.js

@@ -0,0 +1,27 @@
+// @flow
+
+import React from "react";
+
+import type {Assets} from "../webutil/assets";
+import {StaticAdapterSet} from "../explorer/adapters/adapterSet";
+import {StaticAppAdapter as GithubAdapter} from "../plugins/github/appAdapter";
+import {StaticAppAdapter as GitAdapter} from "../plugins/git/appAdapter";
+import {GithubGitGateway} from "../plugins/github/githubGitGateway";
+import {AppPage} from "../explorer/App";
+
+function homepageStaticAdapters(): StaticAdapterSet {
+  return new StaticAdapterSet([
+    new GithubAdapter(),
+    new GitAdapter(new GithubGitGateway()),
+  ]);
+}
+
+export default class HomepageExplorer extends React.Component<{|
+  +assets: Assets,
+|}> {
+  render() {
+    return (
+      <AppPage assets={this.props.assets} adapters={homepageStaticAdapters()} />
+    );
+  }
+}

src/homepage/routeData.js

@@ -38,7 +38,7 @@ const routeData /*: $ReadOnlyArray<RouteDatum> */ = [
     path: "/prototype/",
     contents: {
       type: "PAGE",
-      component: () => require("../explorer/App").default,
+      component: () => require("./homepageExplorer").default,
     },
     title: "SourceCred prototype",
     navTitle: "Prototype",