add Gemini API sample (#1240)

* add Gemini API sample

* Simplify configuration and fix response formatting

* Update wording for gemini nano sample

.gitignore

@@ -4,3 +4,4 @@ node_modules
 # Temporary directory for debugging extension samples
 _debug
 _metadata
+*.swp # vim temp files

functional-samples/ai.gemini-in-the-cloud/.gitignore

@@ -0,0 +1 @@
+dist

functional-samples/ai.gemini-in-the-cloud/README.md

@@ -0,0 +1,23 @@
+# On-device AI with Gemini Nano
+
+This sample demonstrates how to use the Gemini Cloud API in a Chrome Extension.
+
+## Overview
+
+The extension provides a chat interface for the Gemini API. To learn more about the API head over to [https://ai.google.dev/](https://ai.google.dev/).
+
+## Running this extension
+
+1. Clone this repository.
+2. Download the Gemini API client by running:
+   ```sh
+   npm install
+   ```
+3. [Retrieve an API key](https://ai.google.dev/gemini-api/docs/api-key) and update [functional-samples/ai.gemini-in-the-cloud/sidepanel/index.js](functional-samples/ai.gemini-in-the-cloud/sidepanel/index.js) (only for testing).
+4. Compile the JS bundle for the sidepanel implementation by running:
+   ```sh
+   npm run build
+   ```
+5. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+6. Click the extension icon.
+7. Interact with the prompt API in the sidebar.

functional-samples/ai.gemini-in-the-cloud/background.js

@@ -0,0 +1,3 @@
+chrome.sidePanel
+  .setPanelBehavior({ openPanelOnActionClick: true })
+  .catch((error) => console.error(error));

functional-samples/ai.gemini-in-the-cloud/manifest.json

@@ -0,0 +1,22 @@
+{
+  "name": "Google Gemini Demo",
+  "version": "0.1",
+  "manifest_version": 3,
+  "description": "Try the Gemini Models.",
+  "background": {
+    "service_worker": "background.js"
+  },
+  "permissions": ["sidePanel"],
+  "side_panel": {
+    "default_path": "sidepanel/index.html"
+  },
+  "action": {
+    "default_icon": {
+      "16": "images/icon16.png",
+      "32": "images/icon32.png",
+      "48": "images/icon48.png",
+      "128": "images/icon128.png"
+    },
+    "default_title": "Open Chat Interface"
+  }
+}

functional-samples/ai.gemini-in-the-cloud/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "Chrome Extensions Gemini Demo",
+  "version": "1.0",
+  "scripts": {
+    "build": "rollup sidepanel/index.js --file dist/sidepanel.bundle.js --format iife"
+  },
+  "private": true,
+  "devDependencies": {
+    "@google/generative-ai": "0.15.0",
+    "rollup": "4.19.0"
+  }
+}