Use PackageManager to locate installed UWP apps (#26120)

Replaces manual registry crawling with a lookup via
Windows.Management.Deployment.PackageManager. This eliminates the need
for the Registry class.

Covered by existing tests.

Issue: flutter/flutter#81756

Author: cbracken

ci/licenses_golden/licenses_flutter

@@ -1583,9 +1583,6 @@ FILE: ../../../flutter/shell/platform/windows/platform_handler_win32.h
 FILE: ../../../flutter/shell/platform/windows/platform_handler_winuwp.cc
 FILE: ../../../flutter/shell/platform/windows/platform_handler_winuwp.h
 FILE: ../../../flutter/shell/platform/windows/public/flutter_windows.h
-FILE: ../../../flutter/shell/platform/windows/registry.cc
-FILE: ../../../flutter/shell/platform/windows/registry.h
-FILE: ../../../flutter/shell/platform/windows/registry_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/string_conversion.cc
 FILE: ../../../flutter/shell/platform/windows/string_conversion.h
 FILE: ../../../flutter/shell/platform/windows/string_conversion_unittests.cc

shell/platform/windows/BUILD.gn

@@ -171,18 +171,6 @@ source_set("flutter_windows_source") {
   ]
 }
 
-# Windows registry utilities.
-source_set("registry") {
-  sources = [
-    "registry.cc",
-    "registry.h",
-  ]
-
-  if (target_os == "winuwp") {
-    cflags = [ "/EHsc" ]
-  }
-}
-
 # String encoding conversion utilities.
 source_set("string_conversion") {
   sources = [
@@ -233,7 +221,6 @@ executable("flutter_windows_unittests") {
   sources = [
     # "flutter_project_bundle_unittests.cc", //TODO failing due to switches test failing.  Blocked on https://github.com/flutter/flutter/issues/74153
     # "flutter_windows_engine_unittests.cc", //TODO failing to send / receive platform message get plugins working first.  Blocked on https://github.com/flutter/flutter/issues/74155
-    "registry_unittests.cc",
     "string_conversion_unittests.cc",
     "system_utils_unittests.cc",
     "testing/engine_modifier.h",
@@ -273,7 +260,6 @@ executable("flutter_windows_unittests") {
     ":flutter_windows_fixtures",
     ":flutter_windows_headers",
     ":flutter_windows_source",
-    ":registry",
     "//flutter/shell/platform/common:common_cpp",
     "//flutter/shell/platform/embedder:embedder_as_internal_library",
     "//flutter/shell/platform/embedder:embedder_test_utils",
@@ -333,8 +319,6 @@ source_set("uwptool_utils") {
     "uwptool_utils.cc",
     "uwptool_utils.h",
   ]
-
-  deps = [ ":registry" ]
 }
 
 # Command-line tool used by the flutter tool that serves a similar purpose to

shell/platform/windows/registry.cc

@@ -86,7 +86,7 @@ int main(int argc, char** argv) {
     }
 
     // Write an informative message for the user to stderr.
-    std::cerr << "Launched app with package_id " << package_id
+    std::cerr << "Launched app with package ID " << package_id
               << ". PID: " << std::endl;
     // Write the PID to stdout. The flutter tool reads this value in.
     std::cout << process_id << std::endl;

shell/platform/windows/registry.h

@@ -7,6 +7,9 @@
 #include <Windows.h>
 #include <Winreg.h>
 #include <shobjidl_core.h>
+#include <winrt/Windows.ApplicationModel.h>
+#include <winrt/Windows.Foundation.Collections.h>
+#include <winrt/Windows.Management.Deployment.h>
 #include <winrt/base.h>
 
 #include <string>
@@ -41,17 +44,14 @@ int Application::Launch(const std::wstring_view args) {
 }
 
 std::vector<Application> ApplicationStore::GetInstalledApplications() {
-  constexpr wchar_t kMappingsKey[] =
-      L"\\Local Settings\\Software\\Microsoft\\Windows\\CurrentVersion"
-      L"\\AppModel\\Repository\\Families";
-  RegistryKey mappings_key(HKEY_CLASSES_ROOT, kMappingsKey, KEY_READ);
-  if (!mappings_key.IsValid()) {
-    return {};
-  }
+  using winrt::Windows::ApplicationModel::Package;
+  using winrt::Windows::Management::Deployment::PackageManager;
 
+  // Find packages for the current user (default for empty string).
+  PackageManager package_manager;
   std::unordered_set<std::wstring> package_ids;
-  for (const std::wstring& subkey_name : mappings_key.GetSubKeyNames()) {
-    package_ids.emplace(subkey_name);
+  for (const Package& package : package_manager.FindPackagesForUser(L"")) {
+    package_ids.emplace(package.Id().FamilyName().c_str());
   }
   std::vector<Application> apps(package_ids.begin(), package_ids.end());
   return apps;

shell/platform/windows/registry_unittests.cc

@@ -8,8 +8,6 @@
 #include <string>
 #include <vector>
 
-#include "flutter/shell/platform/windows/registry.h"
-
 namespace flutter {
 
 // A UWP application.
@@ -19,7 +17,7 @@ class Application {
   Application(const Application& other) = default;
   Application& operator=(const Application& other) = default;
 
-  // Returns the application user model ID.
+  // Returns the package ID.
   std::wstring GetPackageId() const { return package_id_; }
 
   // Launches the application with the specified list of launch arguments.