Center approval popup over focused window to avoid macOS Space switch

Use getLastFocused to find the current Chrome window and position the
approval popup centered over it. This keeps the popup on the same
macOS virtual desktop instead of switching Spaces.

src/background/index.js

@@ -89,19 +89,32 @@ function requestApproval(origin, hostname) {
         pendingApprovals[id] = { origin, hostname, resolve };
 
         const popupUrl = runtime.getURL("src/popup/index.html?approval=" + id);
-        windowsApi.create(
-            {
+        const popupWidth = 400;
+        const popupHeight = 500;
+
+        // Center the popup over the focused window so macOS keeps it
+        // on the same Space instead of switching desktops.
+        windowsApi.getLastFocused((currentWin) => {
+            const opts = {
                 url: popupUrl,
                 type: "popup",
-                width: 400,
-                height: 500,
-            },
-            (win) => {
+                width: popupWidth,
+                height: popupHeight,
+            };
+            if (currentWin) {
+                opts.left = Math.round(
+                    currentWin.left + (currentWin.width - popupWidth) / 2,
+                );
+                opts.top = Math.round(
+                    currentWin.top + (currentWin.height - popupHeight) / 2,
+                );
+            }
+            windowsApi.create(opts, (win) => {
                 if (win) {
                     pendingApprovals[id].windowId = win.id;
                 }
-            },
-        );
+            });
+        });
     });
 }