Migrate Chrome extension to Manifest Version 3

This concludes the migration work to Manifest version 3. Most of the
necessary changes have been made in other commits since 2022.

Because Manifest Version 3 support requires Chrome 88+, the
minimum_chrome_version has been set to 88 for clarity,
and minimum_opera_version to 74 (which matches Chrome's 88).

The Firefox version is still on Manifest Version 2 since Firefox has not
announced deprecation of Manifest Version 2.

Note: `optional_host_permissions` support was introduced in Chrome 102
(crbug.com/1265064). In Chrome 88 - 101, the extension can only view
Chrome extension sources (with host_permissions) and Firefox add-ons
(with CORS from AMO). Not extensions from other sources.

As a bonugs, another long-standing bug has been fixed: previously, if
Chrome was started with --incognito, then the extension may fail to
initialized because the event page would not wake up. Service workers
always wake up if it has not been activated before for the specific
incognito profile. Because of this, the extension will now initialize
more reliably in incognito windows.

make.js

@@ -183,6 +183,8 @@ target.firefox = function() {
 
     cd(FIREFOX_BUILD_DIR);
     removeTestFiles();
+    // Firefox version uses event page instead of service worker.
+    rm('service_worker.js');
     rm('-f', '../crxviewer_firefox.zip');
     exec('7z a ../crxviewer_firefox.zip * -tzip');
     lintDir(FIREFOX_BUILD_DIR);

src/background.js

@@ -299,19 +299,27 @@ function registerEventRules() {
         pathContains: "addon/"
     }];
 
+    if (!chrome.declarativeContent.ShowAction) {
+        // Chrome < 97.
+        chrome.declarativeContent.ShowAction = chrome.declarativeContent.ShowPageAction;
+    }
+
     var rule = {
         conditions: pageUrlFilters.map(function(pageUrlFilter) {
             return new chrome.declarativeContent.PageStateMatcher({
                 pageUrl: pageUrlFilter,
             });
         }),
         actions: [
-            new chrome.declarativeContent.ShowPageAction(),
+            new chrome.declarativeContent.ShowAction(),
         ],
     };
 
     chrome.declarativeContent.onPageChanged.removeRules(undefined, function() {
-        chrome.declarativeContent.onPageChanged.addRules([rule]);
+        chrome.declarativeContent.onPageChanged.addRules([rule], function() {
+            // Visibility of action fully controlled by declarativeContent.
+            chrome.action.disable();
+        });
     });
 }
 //// The documentation recommends to use runtime.onInstalled to register

src/crxviewer.js

@@ -2142,7 +2142,7 @@ function loadUrlInViewer(crx_url, onHasBlob) {
 //#if CHROME
     function maybeShowPermissionRequest() {
         var permission = {
-            origins: ['<all_urls>']
+            origins: ['*://*/*']
         };
         chrome.permissions.contains(permission, function(hasAccess) {
             if (hasAccess) return;

src/manifest.json

@@ -3,18 +3,12 @@
     "short_name": "CRX Viewer",
     "description": "View source code of Chrome extensions, Firefox addons or Opera extensions (crx/nex/xpi) from the Chrome web store and elsewhere.",
     "version": "1.6.13",
-    "manifest_version": 2,
+    "manifest_version": 3,
+    "minimum_chrome_version": "88",
     "background": {
-        "scripts": [
-            "storage-sync-polyfill.js",
-            "chrome-platform-info.js",
-            "cws_pattern.js",
-            "background.js",
-            "bg-contextmenu.js"
-        ],
-        "persistent": false
+        "service_worker": "service_worker.js"
     },
-    "page_action": {
+    "action": {
         "default_icon": {
             "19": "icons/19.png",
             "38": "icons/38.png"
@@ -29,20 +23,21 @@
     },
     "options_page": "options.html",
     "options_ui": {
-        "page": "options.html#optionsV2",
-        "chrome_style": true
+        "page": "options.html#optionsV2"
     },
     "permissions": [
         "tabs",
         "storage",
         "contextMenus",
         "downloads",
-        "declarativeContent",
+        "declarativeContent"
+    ],
+    "host_permissions": [
         "*://clients2.google.com/service/update2/crx*",
         "*://clients2.googleusercontent.com/crx/download/*"
     ],
-    "optional_permissions": [
-        "<all_urls>"
+    "optional_host_permissions": [
+        "*://*/*"
     ],
     "incognito": "split"
 }

src/manifest_opera.json

@@ -2,22 +2,16 @@
     "name": "Extension source viewer",
     "description": "View source code of extensions in the Chrome Web Store, Firefox or Opera addon gallery. Has button to install from Chrome Web Store.",
     "version": "1.6.13",
-    "manifest_version": 2,
+    "manifest_version": 3,
+    "minimum_opera_version": "74",
     "developer": {
         "name": "Rob Wu",
         "url": "https://robwu.nl"
     },
     "background": {
-        "scripts": [
-            "storage-sync-polyfill.js",
-            "chrome-platform-info.js",
-            "cws_pattern.js",
-            "background.js",
-            "bg-contextmenu.js"
-        ],
-        "persistent": false
+        "service_worker": "service_worker.js"
     },
-    "page_action": {
+    "action": {
         "default_icon": {
             "19": "icons/19.png",
             "38": "icons/38.png"
@@ -36,7 +30,9 @@
         "storage",
         "contextMenus",
         "downloads",
-        "declarativeContent",
+        "declarativeContent"
+    ],
+    "host_permissions": [
         "*://clients2.google.com/service/update2/crx*",
         "*://clients2.googleusercontent.com/crx/download/*",
         "*://addons.opera.com/*",

src/popup.js

@@ -37,7 +37,11 @@ function initialize() {
         crx_url = get_crx_url(cws_url);
         filename = get_zip_name(crx_url);
         if (!can_viewsource_crx_url(crx_url)) {
+//#if FIREFOX
             chrome.pageAction.hide(tabs[0].id);
+//#else
+            chrome.action.disable(tabs[0].id);
+//#endif
             window.close();
             return;
         }

src/service_worker.js

@@ -0,0 +1,10 @@
+"use strict";
+/* globals importScripts */
+
+importScripts(
+    "storage-sync-polyfill.js",
+    "chrome-platform-info.js",
+    "cws_pattern.js",
+    "background.js",
+    "bg-contextmenu.js"
+);