Revert r23330 and r23136 because of a bug with loop invariant code motion.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 23951)
+++ runtime/vm/object.cc	(working copy)
@@ -55,7 +55,6 @@
 DECLARE_FLAG(bool, trace_compiler);
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, enable_type_checks);
-DECLARE_FLAG(int, deoptimization_counter_threshold);
 
 static const char* kGetterPrefix = "get:";
 static const intptr_t kGetterPrefixLength = strlen(kGetterPrefix);
@@ -3446,20 +3445,6 @@
 }
 
 
-void Function::set_deopt_history(const Array& value) const {
-  StorePointer(&raw_ptr()->deopt_history_, value.raw());
-}
-
-
-void Function::EnsureDeoptHistory() const {
-  Array& array = Array::Handle(deopt_history());
-  if (array.IsNull()) {
-    array = Array::New(FLAG_deoptimization_counter_threshold);
-    set_deopt_history(array);
-  }
-}
-
-
 RawContextScope* Function::context_scope() const {
   if (IsClosureFunction()) {
     const Object& obj = Object::Handle(raw_ptr()->data_);