Introduce menu entry support

Summary:
[interesting] since it shows how Flipper APIs are exposed through sandy. However, the next diff is a much simpler example of that

This diff adds support for adding menu entries for sandy plugin (renamed keyboard actions to menus, as it always creates a menu entry, but not necessarily a keyboard shortcut)

```

  client.addMenuEntry(
    // custom entry
    {
      label: 'Reset Selection',
      topLevelMenu: 'Edit',
      handler: () => {
        selectedID.set(null);
      },
    },
    // based on built-in action (sets standard label, shortcut)
    {
      action: 'createPaste',
      handler: () => {
        console.log('creating paste');
      },
    },
  );
```

Most of this diff is introducing the concept of FlipperUtils, a set of static Flipper methods (not related to a device or client) that can be used from Sandy. This will for example be used to implement things as `createPaste` as well

Reviewed By: nikoant

Differential Revision: D22766990

fbshipit-source-id: ce90af3b700e6c3d9a779a3bab4673ba356f3933

desktop/flipper-plugin/src/test-utils/test-utils.tsx

@@ -35,6 +35,7 @@ import {
   DeviceLogListener,
 } from '../plugin/DevicePlugin';
 import {BasePluginInstance} from '../plugin/PluginBase';
+import {FlipperLib} from '../plugin/FlipperLib';
 
 type Renderer = RenderResult<typeof queries>;
 
@@ -61,6 +62,11 @@ type ExtractEventsType<
   : never;
 
 interface BasePluginResult {
+  /**
+   * Mock for Flipper utilities
+   */
+  flipperLib: FlipperLib;
+
   /**
    * Emulates the 'onActivate' event
    */
@@ -84,6 +90,11 @@ interface BasePluginResult {
    * Grab all the persistable state
    */
   exportState(): any;
+
+  /**
+   * Trigger menu entry by label
+   */
+  triggerMenuEntry(label: string): void;
 }
 
 interface StartPluginResult<Module extends FlipperPluginModule<any>>
@@ -165,8 +176,9 @@ export function startPlugin<Module extends FlipperPluginModule<any>>(
   }
 
   const sendStub = jest.fn();
-  const fakeFlipper: RealFlipperClient = {
-    isBackgroundPlugin() {
+  const flipperUtils = createMockFlipperLib();
+  const fakeFlipperClient: RealFlipperClient = {
+    isBackgroundPlugin(_pluginId: string) {
       return !!options?.isBackgroundPlugin;
     },
     initPlugin() {
@@ -186,8 +198,9 @@ export function startPlugin<Module extends FlipperPluginModule<any>>(
   };
 
   const pluginInstance = new SandyPluginInstance(
-    fakeFlipper,
+    flipperUtils,
     definition,
+    fakeFlipperClient,
     options?.initialState,
   );
 
@@ -258,10 +271,12 @@ export function startDevicePlugin<Module extends FlipperDevicePluginModule>(
     );
   }
 
+  const flipperLib = createMockFlipperLib();
   const testDevice = createMockDevice(options);
   const pluginInstance = new SandyDevicePluginInstance(
-    testDevice,
+    flipperLib,
     definition,
+    testDevice,
     options?.initialState,
   );
 
@@ -306,10 +321,17 @@ export function renderDevicePlugin<Module extends FlipperDevicePluginModule>(
   };
 }
 
+export function createMockFlipperLib(): FlipperLib {
+  return {
+    enableMenuEntries: jest.fn(),
+  };
+}
+
 function createBasePluginResult(
   pluginInstance: BasePluginInstance,
 ): BasePluginResult {
   return {
+    flipperLib: pluginInstance.flipperLib,
     activate: () => pluginInstance.activate(),
     deactivate: () => pluginInstance.deactivate(),
     exportState: () => pluginInstance.exportState(),
@@ -317,6 +339,13 @@ function createBasePluginResult(
       pluginInstance.triggerDeepLink(deepLink);
     },
     destroy: () => pluginInstance.destroy(),
+    triggerMenuEntry: (action: string) => {
+      const entry = pluginInstance.menuEntries.find((e) => e.action === action);
+      if (!entry) {
+        throw new Error('No menu entry found with action: ' + action);
+      }
+      entry.handler();
+    },
   };
 }