Add DataReductionProxyExperimentsStats and UMA for measuring potentially non-compressed bytes.

components/data_reduction_proxy/core/browser/data_reduction_proxy_config_retrieval_params.h

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_config_retrieval_params.h
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_retrieval_params.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_retrieval_params.h
new file mode 100644
index 0000000000000000000000000000000000000000..53aa10aba8fc59347e562aa5c9d96d10caf70b2b
--- /dev/null
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_retrieval_params.h
@@ -0,0 +1,154 @@
+// 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_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_RETRIEVAL_PARAMS_H_
+#define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_RETRIEVAL_PARAMS_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+
+class PrefService;
+
+namespace base {
+class HistogramBase;
+}
+
+namespace data_reduction_proxy {
+
+// The number of config fetch variations supported. Must match the number of
+// suffixes in histograms.xml.
+extern const int kConfigFetchGroups;
+
+// The name of the trial group for measuring lost bytes during fetching the
+// configuration.
+extern const char kConfigFetchTrialGroup[];
+
+// The config retrieval round trip time is calculated as:
+// (previous base) * (multiplier) + increment.
+// Multipler is >= 1. Increment is >= 0.
+// The name of the param prefix for determining the base round trip time in
+// milliseconds for simulating a configuration fetch.
+extern const char kConfigRoundtripMillisecondsBaseParam[];
+
+// The name of the param prefix for determining the base round trip time in
+// milliseconds for simulating a configuration fetch.
+extern const char kConfigRoundtripMultiplierParam[];
+
+// The name of the param prefix for determining the base round trip time in
+// milliseconds for simulating a configuration fetch.
+extern const char kConfigRoundtripMillisecondsIncrementParam[];
+
+// The name of the param for determining the expiration interval of the
+// configuration in seconds.
+extern const char kConfigExpirationSecondsParam[];
+
+// The name of the param for determining if the config should be considered
+// stale on startup (regardless of whether it is stale or not).
+extern const char kConfigAlwaysStaleParam[];
+
+// The number of seconds by which the expiration interval exceeds the refresh
+// interval so that we maintain a valid configuration.
+extern const int kConfigFetchBufferSeconds;
+
+// Parameters for setting up an experiment to measure potentially uncompressed
+// bytes during the retrieval of the Data Reduction Proxy configuration.
+class DataReductionProxyConfigRetrievalParams {
+ public:
+  enum ConfigState {
+    VALID = 0,
+    RETRIEVING = 1,
+    EXPIRED = 2,
+  };
+
+  // A variation of the simulated configuration retrieval time, permitting the
+  // experiment to measure multiple values.
+  class Variation {
+   public:
+    Variation(int index, const base::Time& simulated_config_retrieved);
+
+    // Returns the current state of the Data Reduction Proxy configuration.
+    // Virtual for testing.
+    virtual ConfigState GetState(const base::Time& request_time,
+                                 const base::Time& config_expiration) const;
+
+    // Records content length statistics if potentially uncompressed bytes have
+    // been detected for this variation.
+    void RecordStats(int64 received_content_length,
+                     int64 original_content_length) const;
+
+    // Visible for testing.
+    const base::Time& simulated_config_retrieved() const {
+      return simulated_config_retrieved_;
+    }
+
+   private:
+    // The time at which the simulated Data Reduction Proxy configuration is
+    // considered to have been received.
+    base::Time simulated_config_retrieved_;
+
+    // Histograms for recording stats.
+    base::HistogramBase* lost_bytes_ocl_;
+    base::HistogramBase* lost_bytes_rcl_;
+    base::HistogramBase* lost_bytes_diff_;
+  };
+
+  static scoped_ptr<DataReductionProxyConfigRetrievalParams> Create(
+      PrefService* pref_service);
+
+  virtual ~DataReductionProxyConfigRetrievalParams();
+
+  // Records content length statistics against any variations for which
+  // potentially uncompressed bytes have been detected.
+  void RecordStats(const base::Time& request_time,
+                   int64 received_content_length,
+                   int64 original_content_length) const;
+
+  // Simulates retrieving a new configuration.
+  void RefreshConfig();
+
+  bool loaded_expired_config() const { return loaded_expired_config_; }
+
+  // Returns the expiration time of the current configuration.
+  const base::Time& config_expiration() const { return config_expiration_; }
+
+  // Returns how often the configuration should be retrieved.
+  const base::TimeDelta& refresh_interval() const {
+    return config_refresh_interval_;
+  }
+
+  // Visible for testing.
+  const std::vector<Variation>& variations() const { return variations_; }
+
+ private:
+  DataReductionProxyConfigRetrievalParams(
+      bool loaded_expired_config,
+      const std::vector<Variation>& variations,
+      const base::Time& config_expiration,
+      const base::TimeDelta& config_refresh_interval);
+
+  // Indicates that the Data Reduction Proxy configuration when loaded has
+  // expired.
+  bool loaded_expired_config_;
+
+  // The time at which the simulated Data Reduction Proxy configuration
+  // expires.
+  base::Time config_expiration_;
+
+  // The duration for which a Data Reduction Proxy configuration is considered
+  // valid.
+  base::TimeDelta config_expiration_interval_;
+
+  // The duration after which a simulated retrieval of a new Data Reduction
+  // Proxy configuration should be performed.
+  base::TimeDelta config_refresh_interval_;
+
+  // The different variations on roundtrip time that can take place.
+  std::vector<Variation> variations_;
+};
+
+}  // namespace data_reduction_proxy
+#endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_CONFIG_RETRIEVAL_PARAMS_H_