Headers for resource tracking.

chrome/browser/offline_pages/resource_loading_observer.h

Index: chrome/browser/offline_pages/resource_loading_observer.h
diff --git a/chrome/browser/offline_pages/resource_loading_observer.h b/chrome/browser/offline_pages/resource_loading_observer.h
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+// Copyright 2017 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 CHROME_BROWSER_OFFLINE_PAGES_RESOURCE_LOADING_OBSERVER_H_
+#define CHROME_BROWSER_OFFLINE_PAGES_RESOURCE_LOADING_OBSERVER_H_
+
+#include <stdint.h>
+
+namespace offline_pages {
+
+// This interface is used by clients who want to be notified when a resource is
+// requested or completes loading, and to report the size of the resource.
+class ResourceLoadingObserver {
+ public:
+  enum ResourceDataType {
+    IMAGE,
+    TEXT_CSS,
+    OTHER,
+    RESOURCE_DATA_TYPE_COUNT,
+  };
+
+  // Report when a resource starts or completes loading.
+  virtual void ObserveResourceLoading(ResourceDataType type, bool started) = 0;
+
+  // Report how many bytes were received for a resource.
+  virtual void OnNetworkBytesChanged(int64_t received_bytes) = 0;
+};
+
+}  // namespace offline_pages
+
+#endif  // CHROME_BROWSER_OFFLINE_PAGES_RESOURCE_LOADING_OBSERVER_H_