ART: Do some include-what-you-use

Help with transitive includes. In preparation for new
specialized headers reducing transitivity.

Bug: 118385392
Test: mmma art
Change-Id: Ie79afda4e09191428c2b4c2f20a7e3352c01c1e9
diff --git a/dex2oat/dex2oat_test.cc b/dex2oat/dex2oat_test.cc
index 898940a..770b696 100644
--- a/dex2oat/dex2oat_test.cc
+++ b/dex2oat/dex2oat_test.cc
@@ -39,6 +39,7 @@
 #include "dex/dex_file_loader.h"
 #include "dex2oat_environment_test.h"
 #include "dex2oat_return_codes.h"
+#include "gc_root-inl.h"
 #include "intern_table-inl.h"
 #include "oat.h"
 #include "oat_file.h"