sync: Buffer Protocol Events for about:sync page

sync/internal_api/protocol_event_buffer.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sync/internal_api/protocol_event_buffer.h"
+
+#include "sync/internal_api/public/events/protocol_event.h"
+
+namespace syncer {
+
+const size_t ProtocolEventBuffer::kBufferSize = 6;
+
+ProtocolEventBuffer::ProtocolEventBuffer()
+  : buffer_deleter_(&buffer_) {}
+
+ProtocolEventBuffer::~ProtocolEventBuffer() {}
+
+void ProtocolEventBuffer::RecordProtocolEvent(const ProtocolEvent& event) {
+  buffer_.push_back(event.Clone().release());
+  if (buffer_.size() > kBufferSize) {
+    ProtocolEvent* to_delete = buffer_.front();
+    buffer_.pop_front();
+    delete to_delete;
+  }
+}
+
+ScopedVector<ProtocolEvent>
+ProtocolEventBuffer::GetBufferedProtocolEvents() const {
+  ScopedVector<ProtocolEvent> ret;
+  for (std::deque<ProtocolEvent*>::const_iterator it = buffer_.begin();
+       it != buffer_.end(); ++it) {
+    ret.push_back((*it)->Clone().release());
+  }
+  return ret.Pass();
+}
+
+}  // namespace syncer