fix: compile msix as seperate source set

BUILD.gn

@@ -420,6 +420,32 @@ action("electron_generate_node_defines") {
   args = [ rebase_path(target_gen_dir) ] + rebase_path(inputs)
 }
 
+# MSIX updater needs to be in a separate source_set because it uses C++/WinRT
+# headers that require exceptions to be enabled.
+source_set("electron_msix_updater") {
+  sources = [
+    "shell/browser/api/electron_api_msix_updater.cc",
+    "shell/browser/api/electron_api_msix_updater.h",
+  ]
+
+  configs += [ "//third_party/electron_node:node_external_config" ]
+
+  public_configs = [ ":electron_lib_config" ]
+
+  if (is_win) {
+    cflags_cc = [ "/EHsc" ]  # Enable C++ exceptions for C++/WinRT
+
+    include_dirs = [ "//third_party/nearby/src/internal/platform/implementation/windows/generated" ]
+  }
+
+  deps = [
+    "//base",
+    "//content/public/browser",
+    "//gin",
+    "//v8",
+  ]
+}
+
 source_set("electron_lib") {
   configs += [
     "//v8:external_startup_data",
@@ -435,6 +461,7 @@ source_set("electron_lib") {
     ":electron_fuses",
     ":electron_generate_node_defines",
     ":electron_js2c",
+    ":electron_msix_updater",
     ":electron_version_header",
     ":resources",
     "buildflags",
@@ -706,11 +733,6 @@ source_set("electron_lib") {
       "//sandbox/win:sandbox",
       "//third_party/crashpad/crashpad/handler",
     ]
-
-    # Use the pre-generated C++/WinRT headers from //third_party/nearby instead
-    # of the SDK's cppwinrt headers, which may be incomplete. This is needed for
-    # the MSIX auto-updater which uses Windows.ApplicationModel APIs.
-    include_dirs += [ "//third_party/nearby/src/internal/platform/implementation/windows/generated" ]
   }
 
   if (enable_plugins) {

filenames.gni

@@ -279,8 +279,6 @@ filenames = {
     "shell/browser/api/electron_api_in_app_purchase.h",
     "shell/browser/api/electron_api_menu.cc",
     "shell/browser/api/electron_api_menu.h",
-    "shell/browser/api/electron_api_msix_updater.cc",
-    "shell/browser/api/electron_api_msix_updater.h",
     "shell/browser/api/electron_api_native_theme.cc",
     "shell/browser/api/electron_api_native_theme.h",
     "shell/browser/api/electron_api_net_log.cc",