Separated v4l2_metadata into two pieces.

v4l2_metadata and metadata/metadata. The previous design did not work
as intended for testing (it incorrectly assumed that a constructor
would call an overridden method of a child class), plus this way
makes more sense.

BUG: 30140438
Change-Id: I1293535932fed6daed766682421b1215739e17dd
TEST: Unit tests pass
diff --git a/modules/camera/3_4/metadata/metadata.h b/modules/camera/3_4/metadata/metadata.h
new file mode 100644
index 0000000..d25a040
--- /dev/null
+++ b/modules/camera/3_4/metadata/metadata.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2016 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 V4L2_CAMERA_HAL_METADATA_H_
+#define V4L2_CAMERA_HAL_METADATA_H_
+
+#include <hardware/camera3.h>
+
+#include "../common.h"
+#include "partial_metadata_interface.h"
+
+namespace v4l2_camera_hal {
+class Metadata {
+ public:
+  Metadata();
+  virtual ~Metadata();
+
+  int FillStaticMetadata(camera_metadata_t** metadata);
+  bool IsValidRequest(const camera_metadata_t* metadata);
+  int SetRequestSettings(const camera_metadata_t* metadata);
+  int FillResultMetadata(camera_metadata_t** metadata);
+
+ protected:
+  // Helper for the child constructors to fill in metadata components.
+  void AddComponent(std::unique_ptr<PartialMetadataInterface> component);
+
+ private:
+  // The overall metadata is broken down into several distinct pieces.
+  // Note: it is undefined behavior if multiple components share tags.
+  std::vector<std::unique_ptr<PartialMetadataInterface>> components_;
+
+  friend class MetadataTest;
+
+  DISALLOW_COPY_AND_ASSIGN(Metadata);
+};
+
+}  // namespace v4l2_camera_hal
+
+#endif  // V4L2_CAMERA_HAL_V4L2_METADATA_H_