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diff --git a/third_party/content_analysis_sdk/demo/request_queue.h b/third_party/content_analysis_sdk/demo/request_queue.h
new file mode 100644
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+++ b/third_party/content_analysis_sdk/demo/request_queue.h
@@ -0,0 +1,70 @@
+// Copyright 2022 The Chromium Authors.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_ANALYSIS_DEMO_REQUST_QUEUE_H_
+#define CONTENT_ANALYSIS_DEMO_REQUST_QUEUE_H_
+
+#include <condition_variable>
+#include <memory>
+#include <mutex>
+#include <queue>
+
+#include "content_analysis/sdk/analysis_agent.h"
+
+// This class maintains a list of outstanding content analysis requests to
+// process.  Each request is encapsulated in one ContentAnalysisEvent.
+// Requests are handled in FIFO order.
+class RequestQueue {
+ public:
+  using Event = content_analysis::sdk::ContentAnalysisEvent;
+
+  RequestQueue() = default;
+  virtual ~RequestQueue() = default;
+
+  // Push a new content analysis event into the queue.
+  void push(std::unique_ptr<Event> event) {
+    std::lock_guard<std::mutex> lock(mutex_);
+
+    events_.push(std::move(event));
+
+    // Wake before leaving to prevent unpredicatable scheduling.
+    cv_.notify_one();
+  }
+
+  // Pop the next request from the queue, blocking if necessary until an event
+  // is available.  Returns a nullptr if the queue will produce no more
+  // events.
+  std::unique_ptr<Event> pop() {
+    std::unique_lock<std::mutex> lock(mutex_);
+
+    while (!abort_ && events_.size() == 0)
+      cv_.wait(lock);
+
+    std::unique_ptr<Event> event;
+    if (!abort_) {
+      event = std::move(events_.front());
+      events_.pop();
+    }
+
+    return event;
+  }
+
+  // Marks the queue as aborted.  pop() will now return nullptr.
+  void abort() {
+    std::lock_guard<std::mutex> lg(mutex_);
+
+    abort_ = true;
+
+    // Wake before leaving to prevent unpredicatable scheduling.
+    cv_.notify_all();
+  }
+
+ private:
+  std::queue<std::unique_ptr<Event>> events_;
+  std::mutex mutex_;
+  std::condition_variable cv_;
+  bool abort_ = false;
+};
+
+#endif  // CONTENT_ANALYSIS_DEMO_REQUST_QUEUE_H_