Support needed to measure user and service traffic in Chrome.

components/data_use_measurement/core/data_use_user_data.h

Index: components/data_use_measurement/core/data_use_user_data.h
diff --git a/components/data_use_measurement/core/data_use_user_data.h b/components/data_use_measurement/core/data_use_user_data.h
new file mode 100644
index 0000000000000000000000000000000000000000..a516ecaafe67f0d44ec41877c7c3b5f73b078688
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+++ b/components/data_use_measurement/core/data_use_user_data.h
@@ -0,0 +1,55 @@
+// 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_USE_MEASUREMENT_CORE_DATA_USE_USER_DATA_H_
+#define COMPONENTS_DATA_USE_MEASUREMENT_CORE_DATA_USE_USER_DATA_H_
+
+#include "base/supports_user_data.h"
+
+namespace net {
+class URLFetcher;
+}
+
+namespace data_use_measurement {
+
+// Used to annotate URLRequests with the service name if the URLRequest is used
+// by a service.
+class DataUseUserData : public base::SupportsUserData::Data {
+ public:
+  // This enum should be synced with DataUseServices enum in histograms.xml.
+  // Please keep them synced after any updates. Also add service name to
+  // GetServiceName function.
+  enum ServiceType {
+    NOT_TAGGED,
+    SUGGESTIONS,
+  };
+
+  explicit DataUseUserData(ServiceType service_type);
+  ~DataUseUserData() override;
+
+  ServiceType service_type() const { return service_type_; }
+
+  // The key for retrieving back this type of user data.
+  static const void* kUserDataKey;
+
+ private:
+  ServiceType service_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(DataUseUserData);
+};
+
+// Helper function to create DataUseUserData. The caller takes the ownership of
+// the returned object.
+base::SupportsUserData::Data* CreateDataUseUserData(

[Alexei Svitkine (slow), 2015/09/01 20:04:04]

Why not have this as a static Create() on the class?

Also, similar question for the other methods - seems if they're related to the
class, they should be static?

[amohammadkhan, 2015/09/01 23:02:43]

Done.

+    DataUseUserData::ServiceType service);
+
+const char* GetServiceName(DataUseUserData::ServiceType service);
+
+// Services should use this function to attach their |service_type| to the
+// URLFethcer serving them.
+void AttachDataUserUserDataToFetcher(net::URLFetcher* fetcher,
+                                     DataUseUserData::ServiceType service_type);
+
+}  // data_use_measurement namespace
+#endif  // COMPONENTS_DATA_USE_MEASUREMENT_CORE_DATA_USE_USER_DATA_H_