Control data saver pingback reporting fraction with protobuf

components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.h

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.h
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.h
index 75d177196ae837ba1fe7fc9a0f04442854059ce0..7d9623c931a113ab3ac8b84eed593d49c2c7dc88 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.h
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.h
@@ -31,41 +31,52 @@ class DataReductionProxyPingbackClient : public net::URLFetcherDelegate {
   // lifetime of the |DataReductionProxyPingbackClient| instance.
   explicit DataReductionProxyPingbackClient(
       net::URLRequestContextGetter* url_request_context);
   ~DataReductionProxyPingbackClient() override;
 
   // Sends a pingback to the data saver proxy server about various timing
   // information.
   virtual void SendPingback(const DataReductionProxyData& data,
                             const DataReductionProxyPageLoadTiming& timing);
 
+  // Sets the probability of actually sending a pingback to the server for any
+  // call to SendPingback.
+  void SetPingbackReportingFraction(float pingback_reporting_fraction);
+
+ protected:
+  // Generates a float in the range [0, 1). Virtualized in testing.
+  virtual float GenerateRandomFloat() const;
+
  private:
   // URLFetcherDelegate implmentation:
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
-  // Whether a pingback should be sent. Virtualized for testing.
-  virtual bool ShouldSendPingback() const;
+  // Whether a pingback should be sent.
+  bool ShouldSendPingback() const;
 
   // Creates an URLFetcher that will POST to |secure_proxy_url_| using
   // |url_request_context_|. The max retires is set to 5.
   std::unique_ptr<net::URLFetcher> MaybeCreateFetcherForDataAndStart(
       const std::string& data);
 
   net::URLRequestContextGetter* url_request_context_;
 
   // The URL for the data saver proxy's ping back service.
   const GURL pingback_url_;
 
   // The currently running fetcher.
   std::unique_ptr<net::URLFetcher> current_fetcher_;
 
   // Serialized data to send to the data saver proxy server.
   std::list<std::string> data_to_send_;
 
+  // The probability of sending a pingback to the server.
+  float pingback_reporting_fraction_;
+
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(DataReductionProxyPingbackClient);
 };
 
 }  // namespace data_reduction_proxy
 
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_PINGBACK_CLIENT_H_