[ios] Adds launchscreen image assets for Chromium.

ios/chrome/app/resources/BUILD.gn

Index: ios/chrome/app/resources/BUILD.gn
diff --git a/ios/chrome/app/resources/BUILD.gn b/ios/chrome/app/resources/BUILD.gn
index ba5d8676445bec56c2177047ccb8361f27ea73a5..484ebf7ed798cc40abf415e6c9c2ed0b5a1f4733 100644
--- a/ios/chrome/app/resources/BUILD.gn
+++ b/ios/chrome/app/resources/BUILD.gn
@@ -58,3 +58,16 @@ repack("repack_unscaled_resources") {
   output = "$target_gen_dir/resources.pak"
   copy_data_to_bundle = true
 }
+
+bundle_data("launchscreen_assets") {
+  sources = [
+    "launchscreen_images.xcassets/Contents.json",
+    "launchscreen_images.xcassets/launchscreen_app_logo.imageset/Contents.json",
+    "launchscreen_images.xcassets/launchscreen_app_logo.imageset/launchscreen_app_logo.png",
+    "launchscreen_images.xcassets/launchscreen_brand_name.imageset/Contents.json",
+    "launchscreen_images.xcassets/launchscreen_brand_name.imageset/launchscreen_brand_name.png",
+  ]
+  outputs = [
+    "{{bundle_resources_dir}}/{{source_file_part}}",
+  ]
+}