Add support for getting the document title

ext/fg/js/float.js

@@ -162,6 +162,33 @@ class DisplayFloat extends Display {
     setContentScale(scale) {
         document.body.style.fontSize = `${scale}em`;
     }
+
+    async getDocumentTitle() {
+        try {
+            const uniqueId = yomichan.generateId(16);
+
+            const promise = yomichan.getTemporaryListenerResult(
+                chrome.runtime.onMessage,
+                ({action, params}, {resolve}) => {
+                    if (
+                        action === 'documentInformationBroadcast' &&
+                        isObject(params) &&
+                        params.uniqueId === uniqueId &&
+                        params.frameId === 0
+                    ) {
+                        resolve(params);
+                    }
+                },
+                2000
+            );
+            apiForward('requestDocumentInformationBroadcast', {uniqueId});
+
+            const {title} = await promise;
+            return title;
+        } catch (e) {
+            return '';
+        }
+    }
 }
 
 DisplayFloat.instance = new DisplayFloat();

ext/fg/js/frontend.js

@@ -54,7 +54,8 @@ class Frontend extends TextScanner {
 
         this._runtimeMessageHandlers = new Map([
             ['popupSetVisibleOverride', ({visible}) => { this.popup.setVisibleOverride(visible); }],
-            ['rootPopupRequestInformationBroadcast', () => { this._broadcastRootPopupInformation(); }]
+            ['rootPopupRequestInformationBroadcast', () => { this._broadcastRootPopupInformation(); }],
+            ['requestDocumentInformationBroadcast', ({uniqueId}) => { this._broadcastDocumentInformation(uniqueId); }]
         ]);
     }
 
@@ -264,6 +265,14 @@ class Frontend extends TextScanner {
         }
     }
 
+    _broadcastDocumentInformation(uniqueId) {
+        apiForward('documentInformationBroadcast', {
+            uniqueId,
+            frameId: this.popup.frameId,
+            title: document.title
+        });
+    }
+
     async _updatePopupPosition() {
         const textSource = this.getCurrentTextSource();
         if (textSource !== null && await this.popup.isVisible()) {