ART: More header cleanups

Pull out more dependencies through forward declarations.

Test: m test-art-host
Change-Id: I7d86726928937f788b956ec9eac91532d66d57ae
diff --git a/runtime/jit/jit_code_cache.cc b/runtime/jit/jit_code_cache.cc
index 388a517..0cafac7 100644
--- a/runtime/jit/jit_code_cache.cc
+++ b/runtime/jit/jit_code_cache.cc
@@ -35,6 +35,7 @@
 #include "mem_map.h"
 #include "oat_file-inl.h"
 #include "oat_quick_method_header.h"
+#include "object_callbacks.h"
 #include "scoped_thread_state_change-inl.h"
 #include "stack.h"
 #include "thread_list.h"
diff --git a/runtime/jit/jit_code_cache.h b/runtime/jit/jit_code_cache.h
index eea2771..9ecc876 100644
--- a/runtime/jit/jit_code_cache.h
+++ b/runtime/jit/jit_code_cache.h
@@ -29,7 +29,6 @@
 #include "jni.h"
 #include "method_reference.h"
 #include "oat_file.h"
-#include "object_callbacks.h"
 #include "profile_compilation_info.h"
 #include "safe_map.h"
 #include "thread_pool.h"
@@ -39,6 +38,7 @@
 class ArtMethod;
 class LinearAlloc;
 class InlineCache;
+class IsMarkedVisitor;
 class OatQuickMethodHeader;
 class ProfilingInfo;