Lo-Fi snackbar should only be shown for the first q=low response of a page

components/data_reduction_proxy/content/browser/content_lofi_ui_service.h

+// Copyright 2015 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.
+
+#ifndef COMPONENTS_DATA_REDUCTION_PROXY_CONTENT_BROWSER_CONTENT_LOFI_UI_SERVICE_H_
+#define COMPONENTS_DATA_REDUCTION_PROXY_CONTENT_BROWSER_CONTENT_LOFI_UI_SERVICE_H_
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "components/data_reduction_proxy/core/common/lofi_ui_service.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace content {
+class WebContents;
+}
+
+namespace net {
+class URLRequest;
+}
+
+namespace data_reduction_proxy {
+
+typedef base::Callback<void(content::WebContents* web_contents)>
+    OnLoFiResponseReceivedCallback;
+
+// Passes notifications to the UI thread that a Lo-Fi response has been
+// received. These notifications may be used to show Lo-Fi UI. This object lives
+// on the IO thread and OnLoFiReponseReceived should be called from there.
+class ContentLoFiUIService : public LoFiUIService {
+ public:
+  ContentLoFiUIService(
+      const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner,
+      const OnLoFiResponseReceivedCallback& on_lofi_response_received_callback);
+  ~ContentLoFiUIService() override;
+
+  // LoFiUIService implementation:
+  void OnLoFiReponseReceived(const net::URLRequest& request) override;
+
+ private:
+  // Using the |render_process_id| and |render_frame_id|, gets the associated
+  // WebContents if it exists and runs the
+  // |notify_lofi_response_received_callback_|.
+  void OnLoFiResponseReceivedOnUIThread(int render_process_id,
+                                        int render_frame_id);
+
+  // A task runner to post calls to OnLoFiReponseReceivedOnUI on the UI
+  // thread.
+  const scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+  const OnLoFiResponseReceivedCallback on_lofi_response_received_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentLoFiUIService);
+};
+
+}  // namespace data_reduction_proxy
+
+#endif  // COMPONENTS_DATA_REDUCTION_PROXY_CONTENT_BROWSER_CONTENT_LOFI_UI_SERVICE_H_