Remove object_utils.h.

Break into object_lock, field_helper and method_helper.
Clean up header files following this.
Also tidy some of the Handle code in response to compiler errors when resolving
the changes in this CL.

Change-Id: I73e63015a0f02a754d0866bfaf58208aebcaa295
diff --git a/runtime/field_helper.h b/runtime/field_helper.h
new file mode 100644
index 0000000..5eae55e
--- /dev/null
+++ b/runtime/field_helper.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_FIELD_HELPER_H_
+#define ART_RUNTIME_FIELD_HELPER_H_
+
+#include "base/macros.h"
+#include "handle.h"
+#include "mirror/art_field.h"
+
+namespace art {
+
+class FieldHelper {
+ public:
+  explicit FieldHelper(Handle<mirror::ArtField> f) : field_(f) {}
+
+  void ChangeField(mirror::ArtField* new_f) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    DCHECK(new_f != nullptr);
+    field_.Assign(new_f);
+  }
+
+  mirror::ArtField* GetField() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return field_.Get();
+  }
+
+  mirror::Class* GetType(bool resolve = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  // The returned const char* is only guaranteed to be valid for the lifetime of the FieldHelper.
+  // If you need it longer, copy it into a std::string.
+  const char* GetDeclaringClassDescriptor() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ private:
+  Handle<mirror::ArtField> field_;
+  std::string declaring_class_descriptor_;
+
+  DISALLOW_COPY_AND_ASSIGN(FieldHelper);
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_FIELD_HELPER_H_