move ringbuffer interactions to wifi hal

Shallow copy of ringbuffer is stored inside the hal.
The maximum ringbuffer size is configured by the
framework.

overrides IBase::debug to:
1. write ringbuffers in memory to flash (wifi tombstones)
2. write wifi tombstones to lshal debug fd in archived format

Bug: 70171481
Test: compile, run on device
Test: run "lshal debug android.hardware.wifi@1.2::IWifi >>
archive.cpio" and compared archived files with originals using diff command
Change-Id: I33c30e37f245cfa36e005ba8cdc46e91f6de9237
diff --git a/wifi/1.2/default/ringbuffer.h b/wifi/1.2/default/ringbuffer.h
new file mode 100644
index 0000000..4808e40
--- /dev/null
+++ b/wifi/1.2/default/ringbuffer.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2018 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 RINGBUFFER_H_
+#define RINGBUFFER_H_
+
+#include <list>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace wifi {
+namespace V1_2 {
+namespace implementation {
+
+/**
+ * Ringbuffer object used to store debug data.
+ */
+class Ringbuffer {
+   public:
+    explicit Ringbuffer(size_t maxSize);
+
+    // Appends the data buffer and deletes from the front until buffer is
+    // within |maxSize_|.
+    void append(const std::vector<uint8_t>& input);
+    const std::list<std::vector<uint8_t>>& getData() const;
+
+   private:
+    std::list<std::vector<uint8_t>> data_;
+    size_t size_;
+    size_t maxSize_;
+};
+
+}  // namespace implementation
+}  // namespace V1_2
+}  // namespace wifi
+}  // namespace hardware
+}  // namespace android
+
+#endif  // RINGBUFFER_H_