Move plugins to "sonar/desktop/plugins"

Summary:
Plugins moved from "sonar/desktop/src/plugins" to "sonar/desktop/plugins".

Fixed all the paths after moving.

New "desktop" folder structure:
- `src` - Flipper desktop app JS code executing in Electron Renderer (Chrome) process.
- `static` - Flipper desktop app JS code executing in Electron Main (Node.js) process.
- `plugins` - Flipper desktop JS plugins.
- `pkg` - Flipper packaging lib and CLI tool.
- `doctor` - Flipper diagnostics lib and CLI tool.
- `scripts` - Build scripts for Flipper desktop app.
- `headless` - Headless version of Flipper desktop app.
- `headless-tests` - Integration tests running agains Flipper headless version.

Reviewed By: mweststrate

Differential Revision: D20344186

fbshipit-source-id: d020da970b2ea1e001f9061a8782bfeb54e31ba0

desktop/plugins/example/index.tsx

@@ -0,0 +1,116 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {Button, Input, FlipperPlugin, FlexColumn, styled, Text} from 'flipper';
+import React from 'react';
+
+type DisplayMessageResponse = {
+  greeting: string;
+};
+
+type Message = {
+  id: number;
+  msg: string | null | undefined;
+};
+
+type State = {
+  prompt: string;
+  message: string;
+};
+
+type PersistedState = {
+  currentNotificationIds: Array<number>;
+  receivedMessage: string | null;
+};
+
+const Container = styled(FlexColumn)({
+  alignItems: 'center',
+  justifyContent: 'space-around',
+  padding: 20,
+});
+
+export default class Example extends FlipperPlugin<State, any, PersistedState> {
+  static defaultPersistedState = {
+    currentNotificationIds: [],
+    receivedMessage: null,
+  };
+
+  state = {
+    prompt: 'Type a message below to see it displayed on the mobile app',
+    message: '',
+  };
+
+  /*
+   * Reducer to process incoming "send" messages from the mobile counterpart.
+   */
+  static persistedStateReducer(
+    persistedState: PersistedState,
+    method: string,
+    payload: Message,
+  ) {
+    if (method === 'triggerNotification') {
+      return Object.assign({}, persistedState, {
+        currentNotificationIds: persistedState.currentNotificationIds.concat([
+          payload.id,
+        ]),
+      });
+    }
+    if (method === 'displayMessage') {
+      return Object.assign({}, persistedState, {
+        receivedMessage: payload.msg,
+      });
+    }
+    return persistedState;
+  }
+
+  /*
+   * Callback to provide the currently active notifications.
+   */
+  static getActiveNotifications(persistedState: PersistedState) {
+    return persistedState.currentNotificationIds.map((x: number) => {
+      return {
+        id: 'test-notification:' + x,
+        message: 'Example Notification',
+        severity: 'warning' as 'warning',
+        title: 'Notification: ' + x,
+      };
+    });
+  }
+
+  /*
+   * Call a method of the mobile counterpart, to display a message.
+   */
+  sendMessage() {
+    this.client
+      .call('displayMessage', {message: this.state.message || 'Weeeee!'})
+      .then((_params: DisplayMessageResponse) => {
+        this.setState({
+          prompt: 'Nice',
+        });
+      });
+  }
+
+  render() {
+    return (
+      <Container>
+        <Text>{this.state.prompt}</Text>
+        <Input
+          placeholder="Message"
+          onChange={event => {
+            this.setState({message: event.target.value});
+          }}
+        />
+        <Button onClick={this.sendMessage.bind(this)}>Send</Button>
+        {this.props.persistedState.receivedMessage && (
+          <Text> {this.props.persistedState.receivedMessage} </Text>
+        )}
+      </Container>
+    );
+  }
+}

desktop/plugins/example/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "flipper-plugin-example",
+  "version": "1.0.0",
+  "description": "An example for a Flipper plugin",
+  "main": "index.tsx",
+  "license": "MIT",
+  "keywords": ["flipper-plugin"],
+  "title": "Example Plugin",
+  "icon": "apps",
+  "bugs": {
+    "url": "https://fbflipper.com/"
+  }
+}

desktop/plugins/example/yarn.lock

@@ -0,0 +1,4 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+