Replace the bool kDoReadBarrier template parameter with an enum.

Fix one kDoReadBarrier/kIsVolatile mixup in an Object::GetFieldObject
call.

Bug: 12687968

Change-Id: I896b1137b21a20c0504abd2bf3fe6f83805f3300
diff --git a/runtime/read_barrier_option.h b/runtime/read_barrier_option.h
new file mode 100644
index 0000000..7de8b8a
--- /dev/null
+++ b/runtime/read_barrier_option.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2014 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_READ_BARRIER_OPTION_H_
+#define ART_RUNTIME_READ_BARRIER_OPTION_H_
+namespace art {
+
+// Options for performing a read barrier or not.
+enum ReadBarrierOption {
+  kWithReadBarrier,     // Perform a read barrier.
+  kWithoutReadBarrier,  // Don't perform a read barrier.
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_READ_BARRIER_OPTION_H_