Revert of Build Mojo apps in subdirectories, like application packages.

components/html_viewer/BUILD.gn

Index: components/html_viewer/BUILD.gn
diff --git a/components/html_viewer/BUILD.gn b/components/html_viewer/BUILD.gn
index b42649e69cea709853b3d0880cc9d58cf343e1f0..a6b31350619b01a716ed8bb43f4ef4ae86a6194f 100644
--- a/components/html_viewer/BUILD.gn
+++ b/components/html_viewer/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/module_args/v8.gni")
+import("//mojo/mojo_application_package.gni")
 import("//mojo/public/mojo_application.gni")
 import("//testing/test.gni")
 import("//tools/grit/grit_rule.gni")
@@ -167,7 +168,7 @@
   ]
 }
 
-mojo_native_application("html_viewer") {
+mojo_application_package("html_viewer") {
   sources = [
     "html_viewer.cc",
     "ui_setup.h",