Revert "Teach PRESUBMIT.py how to run gn check for most of the mojo repo"

mojo/application_manager/BUILD.gn

Index: mojo/application_manager/BUILD.gn
diff --git a/mojo/application_manager/BUILD.gn b/mojo/application_manager/BUILD.gn
index 44c0f66e6a7b66ff4672315d11d7a4825f1bd87b..f78808638cccb97313304484bdd01bb39d0e174d 100644
--- a/mojo/application_manager/BUILD.gn
+++ b/mojo/application_manager/BUILD.gn
@@ -30,14 +30,11 @@ component("application_manager") {
   ]
   deps = [
     "//base/third_party/dynamic_annotations",
-    "//mojo/edk/system",
-    "//mojo/environment:chromium",
-    "//mojo/public/cpp/application",
-    "//mojo/public/cpp/bindings",
-    "//mojo/public/cpp/system",
-    "//mojo/services/public/interfaces/content_handler",
     "//net",
     "//url",
+    "//mojo/edk/system",
+    "//mojo/environment:chromium",
+    "//mojo/services/public/interfaces/content_handler:content_handler",
   ]
 }