ART: Forward-declare Instrumentation

Avoid header include in a very common header.

Bug: 119869270
Test: mmma art
Change-Id: I6a6f09ad62d61684969635f8cb98b072f3ea781c
diff --git a/runtime/thread.cc b/runtime/thread.cc
index f459f9c..7c050a4 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -73,6 +73,7 @@
 #include "gc_root.h"
 #include "handle_scope-inl.h"
 #include "indirect_reference_table-inl.h"
+#include "instrumentation.h"
 #include "interpreter/interpreter.h"
 #include "interpreter/mterp/mterp.h"
 #include "interpreter/shadow_frame-inl.h"
diff --git a/runtime/thread.h b/runtime/thread.h
index 6db1943..ad69ecf 100644
--- a/runtime/thread.h
+++ b/runtime/thread.h
@@ -36,7 +36,6 @@
 #include "entrypoints/jni/jni_entrypoints.h"
 #include "entrypoints/quick/quick_entrypoints.h"
 #include "handle_scope.h"
-#include "instrumentation.h"
 #include "interpreter/interpreter_cache.h"
 #include "jvalue.h"
 #include "managed_stack.h"
@@ -59,6 +58,10 @@
 }  // namespace collector
 }  // namespace gc
 
+namespace instrumentation {
+struct InstrumentationStackFrame;
+}  // namespace instrumentation
+
 namespace mirror {
 class Array;
 class Class;