Create read only handles for empty_array and sentinel objects

vm/debugger.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 1127 matching lines @@
   return result.raw();
 }
 
 
 RawObject* Debugger::GetStaticField(const Class& cls,
                                     const String& field_name) {
   const Field& fld = Field::Handle(cls.LookupStaticField(field_name));
   if (!fld.IsNull()) {
     // Return the value in the field if it has been initialized already.
     const Instance& value = Instance::Handle(fld.value());
-    ASSERT(value.raw() != Object::transition_sentinel());
-    if (value.raw() != Object::sentinel()) {
+    ASSERT(value.raw() != Object::transition_sentinel().raw());
+    if (value.raw() != Object::sentinel().raw()) {
       return value.raw();
     }
   }
   // There is no field or the field has not been initialized yet.
   // We must have a getter. Run the getter.
   const Function& getter_func =
       Function::Handle(cls.LookupGetterFunction(field_name));
   ASSERT(!getter_func.IsNull());
   if (getter_func.IsNull()) {
     return Object::null();
   }
 
   Object& result = Object::Handle();
   LongJump* base = isolate_->long_jump_base();
   LongJump jump;
   isolate_->set_long_jump_base(&jump);
   bool saved_ignore_flag = ignore_breakpoints_;
   ignore_breakpoints_ = true;
   if (setjmp(*jump.Set()) == 0) {
-    const Array& args = Array::Handle(Object::empty_array());
-    result = DartEntry::InvokeStatic(getter_func, args);
+    result = DartEntry::InvokeStatic(getter_func, Object::empty_array());
   } else {
     result = isolate_->object_store()->sticky_error();
   }
   ignore_breakpoints_ = saved_ignore_flag;
   isolate_->set_long_jump_base(base);
   return result.raw();
 }
 
 
 RawArray* Debugger::GetInstanceFields(const Instance& obj) {
@@ skipping 449 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart