ios: add CrNet

ios/build/packaging/dummy_main.mm

Index: ios/build/packaging/dummy_main.mm
diff --git a/tools/clang/blink_gc_plugin/tests/ref_ptr_to_gc_managed_class.cpp b/ios/build/packaging/dummy_main.mm
similarity index 62%
copy from tools/clang/blink_gc_plugin/tests/ref_ptr_to_gc_managed_class.cpp
copy to ios/build/packaging/dummy_main.mm
index e0a200fed9540f685a11d0e83fbeb2bd48e344c6..20dd1ba9897fabfbc3bd480c374e0526dbdfe90d 100644
--- a/tools/clang/blink_gc_plugin/tests/ref_ptr_to_gc_managed_class.cpp
+++ b/ios/build/packaging/dummy_main.mm
@@ -2,10 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ref_ptr_to_gc_managed_class.h"
-
-namespace blink {
-
-void HeapObject::trace(Visitor*) { }
-
+// Provides a main() function for an empty dummy app.
+int main(int argc, char *argv[]) {
+  return 0;
 }