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diff --git a/chromium/components/query_tiles/logger.h b/chromium/components/query_tiles/logger.h
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+++ b/chromium/components/query_tiles/logger.h
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+// Copyright 2020 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_QUERY_TILES_LOGGER_H_
+#define COMPONENTS_QUERY_TILES_LOGGER_H_
+
+namespace base {
+class Value;
+}
+
+namespace query_tiles {
+
+// A helper class to expose internals of the query-tiles service to a logging
+// component and/or debug UI.
+class Logger {
+ public:
+  class Observer {
+   public:
+    virtual ~Observer() = default;
+
+    // Called whenever the service status changes.
+    virtual void OnServiceStatusChanged(const base::Value& status) = 0;
+
+    // Called when the tile group data is available.
+    virtual void OnTileDataAvailable(const base::Value& status) = 0;
+  };
+
+  virtual ~Logger() = default;
+
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+
+  Logger(const Logger& other) = delete;
+  Logger& operator=(const Logger& other) = delete;
+
+  // Returns the current status of query tile service.
+  // The serialized format will be:
+  // {
+  //  fetcherStatus:[INITIAL, SUCCESS, FAIL, SUSPEND]
+  //  groupStatus:[SUCCESS, UN_INIT, NO_TILES, DB_FAIL]
+  // }
+  virtual base::Value GetServiceStatus() = 0;
+
+  // Returns the formatted raw data stored in database.
+  // The serialized format will be:
+  // {
+  //  groupInfo(string)
+  //  tileProto(string)
+  // }
+  virtual base::Value GetTileData() = 0;
+
+ protected:
+  Logger() = default;
+};
+}  // namespace query_tiles
+#endif  // COMPONENTS_QUERY_TILES_LOGGER_H_