[url_launcher] Endorse url_launcher_linux (#2863)

Adds an endorsement for url_launcher_linux, so that Linux is supported
automatically.

Part of https://github.com/flutter/flutter/issues/41721
diff --git a/packages/url_launcher/url_launcher/CHANGELOG.md b/packages/url_launcher/url_launcher/CHANGELOG.md
index 6b1327a..a536472 100644
--- a/packages/url_launcher/url_launcher/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 5.5.0
+
+* Support Linux by default.
+
 ## 5.4.11
 
 * Add documentation in README suggesting how to properly encode urls with special characters.
@@ -46,7 +50,7 @@
 
 ## 5.4.0
 
-* Support macos by default.
+* Support macOS by default.
 
 ## 5.3.0
 
diff --git a/packages/url_launcher/url_launcher/example/linux/CMakeLists.txt b/packages/url_launcher/url_launcher/example/linux/CMakeLists.txt
new file mode 100644
index 0000000..0236a88
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/CMakeLists.txt
@@ -0,0 +1,95 @@
+cmake_minimum_required(VERSION 3.10)
+project(runner LANGUAGES CXX)
+
+set(BINARY_NAME "example")
+
+cmake_policy(SET CMP0063 NEW)
+
+set(CMAKE_INSTALL_RPATH "$ORIGIN/lib")
+
+# Configure build options.
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+  set(CMAKE_BUILD_TYPE "Debug" CACHE
+    STRING "Flutter build mode" FORCE)
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
+    "Debug" "Profile" "Release")
+endif()
+
+# Compilation settings that should be applied to most targets.
+function(APPLY_STANDARD_SETTINGS TARGET)
+  target_compile_features(${TARGET} PUBLIC cxx_std_14)
+  target_compile_options(${TARGET} PRIVATE -Wall -Werror)
+  target_compile_options(${TARGET} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:-O3>")
+  target_compile_definitions(${TARGET} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:NDEBUG>")
+endfunction()
+
+set(FLUTTER_MANAGED_DIR "${CMAKE_CURRENT_SOURCE_DIR}/flutter")
+
+# Flutter library and tool build rules.
+add_subdirectory(${FLUTTER_MANAGED_DIR})
+
+# System-level dependencies.
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(GTK REQUIRED IMPORTED_TARGET gtk+-3.0)
+
+# Application build
+add_executable(${BINARY_NAME}
+  "main.cc"
+  "my_application.cc"
+  "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
+)
+apply_standard_settings(${BINARY_NAME})
+target_link_libraries(${BINARY_NAME} PRIVATE flutter)
+target_link_libraries(${BINARY_NAME} PRIVATE PkgConfig::GTK)
+add_dependencies(${BINARY_NAME} flutter_assemble)
+
+# Generated plugin build rules, which manage building the plugins and adding
+# them to the application.
+include(flutter/generated_plugins.cmake)
+
+
+# === Installation ===
+# By default, "installing" just makes a relocatable bundle in the build
+# directory.
+set(BUILD_BUNDLE_DIR "${PROJECT_BINARY_DIR}/bundle")
+if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
+  set(CMAKE_INSTALL_PREFIX "${BUILD_BUNDLE_DIR}" CACHE PATH "..." FORCE)
+endif()
+
+# Start with a clean build bundle directory every time.
+install(CODE "
+  file(REMOVE_RECURSE \"${BUILD_BUNDLE_DIR}/\")
+  " COMPONENT Runtime)
+
+set(INSTALL_BUNDLE_DATA_DIR "${CMAKE_INSTALL_PREFIX}/data")
+set(INSTALL_BUNDLE_LIB_DIR "${CMAKE_INSTALL_PREFIX}/lib")
+
+install(TARGETS ${BINARY_NAME} RUNTIME DESTINATION "${CMAKE_INSTALL_PREFIX}"
+  COMPONENT Runtime)
+
+install(FILES "${FLUTTER_ICU_DATA_FILE}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}"
+  COMPONENT Runtime)
+
+install(FILES "${FLUTTER_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+  COMPONENT Runtime)
+
+if(PLUGIN_BUNDLED_LIBRARIES)
+  install(FILES "${PLUGIN_BUNDLED_LIBRARIES}"
+    DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+    COMPONENT Runtime)
+endif()
+
+# Fully re-copy the assets directory on each build to avoid having stale files
+# from a previous install.
+set(FLUTTER_ASSET_DIR_NAME "flutter_assets")
+install(CODE "
+  file(REMOVE_RECURSE \"${INSTALL_BUNDLE_DATA_DIR}/${FLUTTER_ASSET_DIR_NAME}\")
+  " COMPONENT Runtime)
+install(DIRECTORY "${PROJECT_BUILD_DIR}/${FLUTTER_ASSET_DIR_NAME}"
+  DESTINATION "${INSTALL_BUNDLE_DATA_DIR}" COMPONENT Runtime)
+
+# Install the AOT library on non-Debug builds only.
+if(NOT CMAKE_BUILD_TYPE MATCHES "Debug")
+  install(FILES "${AOT_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+    COMPONENT Runtime)
+endif()
diff --git a/packages/url_launcher/url_launcher/example/linux/flutter/CMakeLists.txt b/packages/url_launcher/url_launcher/example/linux/flutter/CMakeLists.txt
new file mode 100644
index 0000000..94f43ff
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/flutter/CMakeLists.txt
@@ -0,0 +1,86 @@
+cmake_minimum_required(VERSION 3.10)
+
+set(EPHEMERAL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ephemeral")
+
+# Configuration provided via flutter tool.
+include(${EPHEMERAL_DIR}/generated_config.cmake)
+
+# TODO: Move the rest of this into files in ephemeral. See
+# https://github.com/flutter/flutter/issues/57146.
+
+# Serves the same purpose as list(TRANSFORM ... PREPEND ...),
+# which isn't available in 3.10.
+function(list_prepend LIST_NAME PREFIX)
+    set(NEW_LIST "")
+    foreach(element ${${LIST_NAME}})
+        list(APPEND NEW_LIST "${PREFIX}${element}")
+    endforeach(element)
+    set(${LIST_NAME} "${NEW_LIST}" PARENT_SCOPE)
+endfunction()
+
+# === Flutter Library ===
+# System-level dependencies.
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(GTK REQUIRED IMPORTED_TARGET gtk+-3.0)
+pkg_check_modules(GLIB REQUIRED IMPORTED_TARGET glib-2.0)
+pkg_check_modules(GIO REQUIRED IMPORTED_TARGET gio-2.0)
+
+set(FLUTTER_LIBRARY "${EPHEMERAL_DIR}/libflutter_linux_gtk.so")
+
+# Published to parent scope for install step.
+set(FLUTTER_LIBRARY ${FLUTTER_LIBRARY} PARENT_SCOPE)
+set(FLUTTER_ICU_DATA_FILE "${EPHEMERAL_DIR}/icudtl.dat" PARENT_SCOPE)
+set(PROJECT_BUILD_DIR "${PROJECT_DIR}/build/" PARENT_SCOPE)
+set(AOT_LIBRARY "${PROJECT_DIR}/build/lib/libapp.so" PARENT_SCOPE)
+
+list(APPEND FLUTTER_LIBRARY_HEADERS
+  "fl_basic_message_channel.h"
+  "fl_binary_codec.h"
+  "fl_binary_messenger.h"
+  "fl_dart_project.h"
+  "fl_engine.h"
+  "fl_json_message_codec.h"
+  "fl_json_method_codec.h"
+  "fl_message_codec.h"
+  "fl_method_call.h"
+  "fl_method_channel.h"
+  "fl_method_codec.h"
+  "fl_method_response.h"
+  "fl_plugin_registrar.h"
+  "fl_plugin_registry.h"
+  "fl_standard_message_codec.h"
+  "fl_standard_method_codec.h"
+  "fl_string_codec.h"
+  "fl_value.h"
+  "fl_view.h"
+  "flutter_linux.h"
+)
+list_prepend(FLUTTER_LIBRARY_HEADERS "${EPHEMERAL_DIR}/flutter_linux/")
+add_library(flutter INTERFACE)
+target_include_directories(flutter INTERFACE
+  "${EPHEMERAL_DIR}"
+)
+target_link_libraries(flutter INTERFACE "${FLUTTER_LIBRARY}")
+target_link_libraries(flutter INTERFACE
+  PkgConfig::GTK
+  PkgConfig::GLIB
+  PkgConfig::GIO
+)
+add_dependencies(flutter flutter_assemble)
+
+# === Flutter tool backend ===
+# _phony_ is a non-existent file to force this command to run every time,
+# since currently there's no way to get a full input/output list from the
+# flutter tool.
+add_custom_command(
+  OUTPUT ${FLUTTER_LIBRARY} ${FLUTTER_LIBRARY_HEADERS}
+    ${CMAKE_CURRENT_BINARY_DIR}/_phony_
+  COMMAND ${CMAKE_COMMAND} -E env
+    ${FLUTTER_TOOL_ENVIRONMENT}
+    "${FLUTTER_ROOT}/packages/flutter_tools/bin/tool_backend.sh"
+      linux-x64 ${CMAKE_BUILD_TYPE}
+)
+add_custom_target(flutter_assemble DEPENDS
+  "${FLUTTER_LIBRARY}"
+  ${FLUTTER_LIBRARY_HEADERS}
+)
diff --git a/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugin_registrant.cc b/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugin_registrant.cc
new file mode 100644
index 0000000..026851f
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugin_registrant.cc
@@ -0,0 +1,13 @@
+//
+//  Generated file. Do not edit.
+//
+
+#include "generated_plugin_registrant.h"
+
+#include <url_launcher_linux/url_launcher_plugin.h>
+
+void fl_register_plugins(FlPluginRegistry* registry) {
+  g_autoptr(FlPluginRegistrar) url_launcher_linux_registrar =
+      fl_plugin_registry_get_registrar_for_plugin(registry, "UrlLauncherPlugin");
+  url_launcher_plugin_register_with_registrar(url_launcher_linux_registrar);
+}
diff --git a/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugin_registrant.h b/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugin_registrant.h
new file mode 100644
index 0000000..9bf7478
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugin_registrant.h
@@ -0,0 +1,13 @@
+//
+//  Generated file. Do not edit.
+//
+
+#ifndef GENERATED_PLUGIN_REGISTRANT_
+#define GENERATED_PLUGIN_REGISTRANT_
+
+#include <flutter_linux/flutter_linux.h>
+
+// Registers Flutter plugins.
+void fl_register_plugins(FlPluginRegistry* registry);
+
+#endif  // GENERATED_PLUGIN_REGISTRANT_
diff --git a/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugins.cmake b/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugins.cmake
new file mode 100644
index 0000000..1fc8ed3
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/flutter/generated_plugins.cmake
@@ -0,0 +1,16 @@
+#
+# Generated file, do not edit.
+#
+
+list(APPEND FLUTTER_PLUGIN_LIST
+  url_launcher_linux
+)
+
+set(PLUGIN_BUNDLED_LIBRARIES)
+
+foreach(plugin ${FLUTTER_PLUGIN_LIST})
+  add_subdirectory(flutter/ephemeral/.plugin_symlinks/${plugin}/linux plugins/${plugin})
+  target_link_libraries(${BINARY_NAME} PRIVATE ${plugin}_plugin)
+  list(APPEND PLUGIN_BUNDLED_LIBRARIES $<TARGET_FILE:${plugin}_plugin>)
+  list(APPEND PLUGIN_BUNDLED_LIBRARIES ${${plugin}_bundled_libraries})
+endforeach(plugin)
diff --git a/packages/url_launcher/url_launcher/example/linux/main.cc b/packages/url_launcher/url_launcher/example/linux/main.cc
new file mode 100644
index 0000000..e7c5c54
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/main.cc
@@ -0,0 +1,6 @@
+#include "my_application.h"
+
+int main(int argc, char** argv) {
+  g_autoptr(MyApplication) app = my_application_new();
+  return g_application_run(G_APPLICATION(app), argc, argv);
+}
diff --git a/packages/url_launcher/url_launcher/example/linux/my_application.cc b/packages/url_launcher/url_launcher/example/linux/my_application.cc
new file mode 100644
index 0000000..c2357f1
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/my_application.cc
@@ -0,0 +1,44 @@
+#include "my_application.h"
+
+#include <flutter_linux/flutter_linux.h>
+
+#include "flutter/generated_plugin_registrant.h"
+
+struct _MyApplication {
+  GtkApplication parent_instance;
+};
+
+G_DEFINE_TYPE(MyApplication, my_application, GTK_TYPE_APPLICATION)
+
+// Implements GApplication::activate.
+static void my_application_activate(GApplication* application) {
+  GtkWindow* window =
+      GTK_WINDOW(gtk_application_window_new(GTK_APPLICATION(application)));
+  GtkHeaderBar *header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
+  gtk_widget_show(GTK_WIDGET(header_bar));
+  gtk_header_bar_set_title(header_bar, "example");
+  gtk_header_bar_set_show_close_button(header_bar, TRUE);
+  gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
+  gtk_window_set_default_size(window, 1280, 720);
+  gtk_widget_show(GTK_WIDGET(window));
+
+  g_autoptr(FlDartProject) project = fl_dart_project_new();
+
+  FlView* view = fl_view_new(project);
+  gtk_widget_show(GTK_WIDGET(view));
+  gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));
+
+  fl_register_plugins(FL_PLUGIN_REGISTRY(view));
+
+  gtk_widget_grab_focus(GTK_WIDGET(view));
+}
+
+static void my_application_class_init(MyApplicationClass* klass) {
+  G_APPLICATION_CLASS(klass)->activate = my_application_activate;
+}
+
+static void my_application_init(MyApplication* self) {}
+
+MyApplication* my_application_new() {
+  return MY_APPLICATION(g_object_new(my_application_get_type(), nullptr));
+}
diff --git a/packages/url_launcher/url_launcher/example/linux/my_application.h b/packages/url_launcher/url_launcher/example/linux/my_application.h
new file mode 100644
index 0000000..72271d5
--- /dev/null
+++ b/packages/url_launcher/url_launcher/example/linux/my_application.h
@@ -0,0 +1,18 @@
+#ifndef FLUTTER_MY_APPLICATION_H_
+#define FLUTTER_MY_APPLICATION_H_
+
+#include <gtk/gtk.h>
+
+G_DECLARE_FINAL_TYPE(MyApplication, my_application, MY, APPLICATION,
+                     GtkApplication)
+
+/**
+ * my_application_new:
+ *
+ * Creates a new Flutter-based application.
+ *
+ * Returns: a new #MyApplication.
+ */
+MyApplication* my_application_new();
+
+#endif  // FLUTTER_MY_APPLICATION_H_
diff --git a/packages/url_launcher/url_launcher/example/test_driver/url_launcher_e2e.dart b/packages/url_launcher/url_launcher/example/test_driver/url_launcher_e2e.dart
index e1d75f9..6cf1168 100644
--- a/packages/url_launcher/url_launcher/example/test_driver/url_launcher_e2e.dart
+++ b/packages/url_launcher/url_launcher/example/test_driver/url_launcher_e2e.dart
@@ -2,6 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:io' show Platform;
+
+import 'package:flutter/foundation.dart' show kIsWeb;
 import 'package:flutter_test/flutter_test.dart';
 import 'package:e2e/e2e.dart';
 import 'package:url_launcher/url_launcher.dart';
@@ -15,8 +18,10 @@
     // Generally all devices should have some default browser.
     expect(await canLaunch('http://flutter.dev'), true);
 
-    // Generally all devices should have some default SMS app.
-    expect(await canLaunch('sms:5555555555'), true);
+    // SMS handling is available by default on most platforms.
+    if (kIsWeb || !Platform.isLinux) {
+      expect(await canLaunch('sms:5555555555'), true);
+    }
 
     // tel: and mailto: links may not be openable on every device. iOS
     // simulators notably can't open these link types.
diff --git a/packages/url_launcher/url_launcher/pubspec.yaml b/packages/url_launcher/url_launcher/pubspec.yaml
index 08ac3f9..299de93 100644
--- a/packages/url_launcher/url_launcher/pubspec.yaml
+++ b/packages/url_launcher/url_launcher/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Flutter plugin for launching a URL on Android and iOS. Supports
   web, phone, SMS, and email schemes.
 homepage: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher
-version: 5.4.11
+version: 5.5.0
 
 flutter:
   plugin:
@@ -14,6 +14,8 @@
         pluginClass: FLTURLLauncherPlugin
       web:
         default_package: url_launcher_web
+      linux:
+        default_package: url_laucher_linux
       macos:
         default_package: url_laucher_macos
 
@@ -27,6 +29,7 @@
   # TODO(amirh): Revisit this (either update this part in the  design or the pub tool).
   # https://github.com/flutter/flutter/issues/46264
   url_launcher_web: ^0.1.0+1
+  url_launcher_linux: ^0.0.1
   url_launcher_macos: ^0.0.1
 
 dev_dependencies:
diff --git a/packages/url_launcher/url_launcher_linux/CHANGELOG.md b/packages/url_launcher/url_launcher_linux/CHANGELOG.md
index 18ba82a..e03b1d3 100644
--- a/packages/url_launcher/url_launcher_linux/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher_linux/CHANGELOG.md
@@ -1,2 +1,5 @@
+# 0.0.1+1
+* README update for endorsement by url_launcher.
+
 # 0.0.1
 * The initial implementation of url_launcher for Linux
diff --git a/packages/url_launcher/url_launcher_linux/README.md b/packages/url_launcher/url_launcher_linux/README.md
index 9b16bdf..0474c58 100644
--- a/packages/url_launcher/url_launcher_linux/README.md
+++ b/packages/url_launcher/url_launcher_linux/README.md
@@ -6,10 +6,22 @@
 
 ### Import the package
 
-This package is an unendorsed Linux implementation of `url_launcher`.
+This package has been endorsed, meaning that you only need to add `url_launcher`
+as a dependency in your `pubspec.yaml`. It will be automatically included in your app
+when you depend on `package:url_launcher`.
 
-In order to use this now, you'll need to depend on `url_launcher_linux`.
-When this package is endorsed it will be automatically used by the `url_launcher` package and you can switch to that API.
+This is what the above means to your `pubspec.yaml`:
+
+```yaml
+...
+dependencies:
+  ...
+  url_launcher: ^5.5.0
+  ...
+```
+
+If you wish to use the Linux package only, you can add  `url_launcher_linux` as a
+dependency:
 
 ```yaml
 ...
diff --git a/packages/url_launcher/url_launcher_linux/pubspec.yaml b/packages/url_launcher/url_launcher_linux/pubspec.yaml
index 2662176..74c2968 100644
--- a/packages/url_launcher/url_launcher_linux/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_linux/pubspec.yaml
@@ -1,6 +1,6 @@
 name: url_launcher_linux
 description: Linux implementation of the url_launcher plugin.
-version: 0.0.1
+version: 0.0.1+1
 homepage: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher_linux
 
 flutter:
diff --git a/script/build_all_plugins_app.sh b/script/build_all_plugins_app.sh
index 262c4ed..961cecc 100755
--- a/script/build_all_plugins_app.sh
+++ b/script/build_all_plugins_app.sh
@@ -31,6 +31,7 @@
   "shared_preferences_platform_interface"
   "shared_preferences_web"
   "shared_preferences_windows"
+  "url_launcher_linux"
   "url_launcher_macos"
   "url_launcher_platform_interface"
   "url_launcher_web"