make clipboardRead an optional permission

ext/bg/js/search.js

@@ -85,7 +85,16 @@ class DisplaySearch extends Display {
             if (this.clipboardMonitorEnable !== null) {
                 this.clipboardMonitorEnable.addEventListener('change', (e) => {
                     if (e.target.checked) {
-                        this.startClipboardMonitor();
+                        chrome.permissions.request(
+                            {permissions: ['clipboardRead']},
+                            (granted) => {
+                                if (granted) {
+                                    this.startClipboardMonitor();
+                                } else {
+                                    e.target.checked = false;
+                                }
+                            }
+                        );
                     } else {
                         this.stopClipboardMonitor();
                     }

ext/manifest.json

@@ -41,10 +41,12 @@
     "permissions": [
         "<all_urls>",
         "storage",
-        "clipboardRead",
         "clipboardWrite",
         "unlimitedStorage"
     ],
+    "optional_permissions": [
+        "clipboardRead"
+    ],
     "commands": {
         "toggle": {
             "suggested_key": {