content: Open links in-app on Android

`url_launcher` plugin now supports the desired behavior, which is using
Android Custom Tabs, so we don't need the workaround of opening the
links in external browser anymore, thus removed them.

Upstream PR:
 flutter/packages#4739

Fixes #279

Author: rajveermalviya

lib/widgets/content.dart

@@ -673,15 +673,7 @@ void _launchUrl(BuildContext context, String urlString) async {
   bool launched = false;
   String? errorMessage;
   try {
-    launched = await ZulipBinding.instance.launchUrl(url,
-      mode: switch (Theme.of(context).platform) {
-        // TODO(#279): On Android we settle for LaunchMode.externalApplication
-        //   because url_launcher's in-app is a weirdly bare UX.
-        //   Switch once that's fixed upstream (by us or otherwise).
-        TargetPlatform.android => UrlLaunchMode.externalApplication,
-        _ => UrlLaunchMode.platformDefault,
-      },
-    );
+    launched = await ZulipBinding.instance.launchUrl(url);
   } on PlatformException catch (e) {
     errorMessage = e.message;
   }

pubspec.lock

@@ -921,26 +921,26 @@ packages:
     dependency: "direct main"
     description:
       name: url_launcher
-      sha256: "781bd58a1eb16069412365c98597726cd8810ae27435f04b3b4d3a470bacd61e"
+      sha256: "47e208a6711459d813ba18af120d9663c20bdf6985d6ad39fe165d2538378d27"
       url: "https://pub.dev"
     source: hosted
-    version: "6.1.12"
+    version: "6.1.14"
   url_launcher_android:
     dependency: transitive
     description:
       name: url_launcher_android
-      sha256: "3dd2388cc0c42912eee04434531a26a82512b9cb1827e0214430c9bcbddfe025"
+      sha256: b04af59516ab45762b2ca6da40fa830d72d0f6045cd97744450b73493fa76330
       url: "https://pub.dev"
     source: hosted
-    version: "6.0.38"
+    version: "6.1.0"
   url_launcher_ios:
     dependency: transitive
     description:
       name: url_launcher_ios
-      sha256: "9af7ea73259886b92199f9e42c116072f05ff9bea2dcb339ab935dfc957392c2"
+      sha256: "7c65021d5dee51813d652357bc65b8dd4a6177082a9966bc8ba6ee477baa795f"
       url: "https://pub.dev"
     source: hosted
-    version: "6.1.4"
+    version: "6.1.5"
   url_launcher_linux:
     dependency: transitive
     description:
@@ -953,10 +953,10 @@ packages:
     dependency: transitive
     description:
       name: url_launcher_macos
-      sha256: "1c4fdc0bfea61a70792ce97157e5cc17260f61abbe4f39354513f39ec6fd73b1"
+      sha256: b55486791f666e62e0e8ff825e58a023fd6b1f71c49926483f1128d3bbd8fe88
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.6"
+    version: "3.0.7"
   url_launcher_platform_interface:
     dependency: transitive
     description:

pubspec.yaml

@@ -56,7 +56,7 @@ dependencies:
   image_picker: ^1.0.0
   package_info_plus: ^4.0.1
   collection: ^1.17.2
-  url_launcher: ^6.1.11
+  url_launcher: ^6.1.14
 
 dev_dependencies:
   flutter_test:

test/widgets/content_test.dart

@@ -1,7 +1,6 @@
 import 'dart:io';
 
 import 'package:checks/checks.dart';
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:url_launcher/url_launcher.dart';
@@ -57,8 +56,6 @@ void main() {
   });
 
   group('LinkNode interactions', () {
-    const expectedModeAndroid = LaunchMode.externalApplication;
-
     // The Flutter test font uses square glyphs, so width equals height:
     //   https://github.com/flutter/flutter/wiki/Flutter-Test-Fonts
     const fontSize = 48.0;
@@ -80,10 +77,8 @@ void main() {
         '<p><a href="https://example/">hello</a></p>');
 
       await tester.tap(find.text('hello'));
-      final expectedMode = defaultTargetPlatform == TargetPlatform.android ?
-        LaunchMode.externalApplication : LaunchMode.platformDefault;
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://example/'), mode: expectedMode));
+        .single.equals((url: Uri.parse('https://example/'), mode: LaunchMode.platformDefault));
     }, variant: const TargetPlatformVariant({TargetPlatform.android, TargetPlatform.iOS}));
 
     testWidgets('multiple links in paragraph', (tester) async {
@@ -97,19 +92,19 @@ void main() {
 
       await tester.tapAt(base.translate(1*fontSize, 0)); // "fXo bar baz"
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://a/'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('https://a/'), mode: LaunchMode.platformDefault));
 
       await tester.tapAt(base.translate(9*fontSize, 0)); // "foo bar bXz"
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://b/'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('https://b/'), mode: LaunchMode.platformDefault));
     });
 
     testWidgets('link nested in other spans', (tester) async {
       await prepareContent(tester,
         '<p><strong><em><a href="https://a/">word</a></em></strong></p>');
       await tester.tap(find.text('word'));
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://a/'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('https://a/'), mode: LaunchMode.platformDefault));
     });
 
     testWidgets('link containing other spans', (tester) async {
@@ -120,27 +115,27 @@ void main() {
 
       await tester.tapAt(base.translate(1*fontSize, 0)); // "tXo words"
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://a/'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('https://a/'), mode: LaunchMode.platformDefault));
 
       await tester.tapAt(base.translate(6*fontSize, 0)); // "two woXds"
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://a/'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('https://a/'), mode: LaunchMode.platformDefault));
     });
 
     testWidgets('relative links are resolved', (tester) async {
       await prepareContent(tester,
         '<p><a href="/a/b?c#d">word</a></p>');
       await tester.tap(find.text('word'));
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('${eg.realmUrl}a/b?c#d'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('${eg.realmUrl}a/b?c#d'), mode: LaunchMode.platformDefault));
     });
 
     testWidgets('link inside HeadingNode', (tester) async {
       await prepareContent(tester,
         '<h6><a href="https://a/">word</a></h6>');
       await tester.tap(find.text('word'));
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('https://a/'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('https://a/'), mode: LaunchMode.platformDefault));
     });
 
     testWidgets('error dialog if invalid link', (tester) async {
@@ -150,7 +145,7 @@ void main() {
       await tester.tap(find.text('word'));
       await tester.pump();
       check(testBinding.takeLaunchUrlCalls())
-        .single.equals((url: Uri.parse('file:///etc/bad'), mode: expectedModeAndroid));
+        .single.equals((url: Uri.parse('file:///etc/bad'), mode: LaunchMode.platformDefault));
       checkErrorDialog(tester, expectedTitle: 'Unable to open link');
     });
   });