Convert Tab Flipper to MV3 (#679)

api/default_command_override/background.js

@@ -0,0 +1,16 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+chrome.commands.onCommand.addListener(async (command) => {
+  const tabs = await chrome.tabs.query({ currentWindow: true });
+  // Sort tabs according to their index in the window.
+  tabs.sort((a, b) => { return a.index < b.index; });
+  let activeIndex = tabs.findIndex((tab) => { return tab.active; });
+  let lastTab = tabs.length - 1;
+  let newIndex = -1;
+  if (command === 'flip-tabs-forward')
+    newIndex = activeIndex === 0 ? lastTab : activeIndex - 1;
+  else  // 'flip-tabs-backwards'
+    newIndex = activeIndex === lastTab ? 0 : activeIndex + 1;
+  chrome.tabs.update(tabs[newIndex].id, { active: true, highlighted: true });
+});

api/default_command_override/manifest.json

@@ -0,0 +1,35 @@
+{
+  "name": "Tab Flipper",
+  "description": "Press Ctrl+Shift+Right or Ctrl+Shift+Left (Command+Shift+Right or Command+Shift+Left on a Mac) to flip through window tabs",
+  "version": "1.0",
+  "manifest_version": 3,
+  "background": {
+    "service_worker": "background.js"
+  },
+  "action": {
+    "default_icon": "images/tabFlipper16.png",
+    "default_title": "Press Ctrl(Win)/Command(Mac)+Shift+ Left or Right to Flip Tabs"
+  },
+  "commands": {
+    "flip-tabs-forward": {
+      "suggested_key": {
+        "default": "Ctrl+Shift+Right",
+        "mac": "Command+Shift+Right"
+      },
+      "description": "Flip tabs forward"
+    },
+    "flip-tabs-backwards": {
+      "suggested_key": {
+        "default": "Ctrl+Shift+Left",
+        "mac": "Command+Shift+Left"
+      },
+      "description": "Flip tabs backwards"
+    }
+  },
+  "icons": {
+    "16": "images/tabFlipper16.png",
+    "32": "images/tabFlipper32.png",
+    "48": "images/tabFlipper48.png",
+    "128": "images/tabFlipper128.png"
+  }
+}