FXIOS-7871 mozilla-mobile#17571 ⁃ Opening a link in external app leav…

…es a "loading" about:blank page behind (mozilla-mobile#19288)

Co-authored-by: Alexandru Farcasanu <c_afarcasanu@groupon.com>

firefox-ios/Client/Frontend/Browser/BrowserViewController/Extensions/BrowserViewController+WebViewDelegates.swift

@@ -33,6 +33,11 @@ extension BrowserViewController: WKUIDelegate {
             screenshotHelper.takeScreenshot(currentTab)
         }
 
+        if navigationAction.canOpenExternalApp, let url = navigationAction.request.url {
+            UIApplication.shared.open(url)
+            return nil
+        }
+
         // If the page uses `window.open()` or `[target="_blank"]`, open the page in a new tab.
         // IMPORTANT!!: WebKit will perform the `URLRequest` automatically!! Attempting to do
         // the request here manually leads to incorrect results!!
@@ -1082,4 +1087,14 @@ extension WKNavigationAction {
             return false
         }
     }
+
+    var canOpenExternalApp: Bool {
+        guard let urlShortDomain = request.url?.shortDomain else { return false }
+
+        if let url = URL(string: "\(urlShortDomain)://"), UIApplication.shared.canOpenURL(url) {
+            return true
+        }
+
+        return false
+    }
 }

firefox-ios/Client/Info.plist

@@ -55,6 +55,9 @@
 	<false/>
 	<key>LSApplicationQueriesSchemes</key>
 	<array>
+		<string>paypal</string>
+		<string>instagram</string>
+		<string>youtube</string>
 		<string>pocket</string>
 		<string>firefox-focus</string>
 		<string>firefox-klar</string>