Precache should cancel when there is user traffic

components/data_use_measurement/content/data_use_measurement.h

Index: components/data_use_measurement/content/data_use_measurement.h
diff --git a/components/data_use_measurement/content/data_use_measurement.h b/components/data_use_measurement/content/data_use_measurement.h
index babaeade50dd03586f36333f8c35b4cd67be902c..55046c76a3511eb65b235d1c3392166b7a5386d8 100644
--- a/components/data_use_measurement/content/data_use_measurement.h
+++ b/components/data_use_measurement/content/data_use_measurement.h
@@ -41,6 +41,9 @@ class DataUseMeasurement {
   // Records the data use of the |request|, thus |request| must be non-null.
   void ReportDataUseUMA(const net::URLRequest* request) const;
 
+  // Returns true if the URLRequest |request| is initiated by user traffic.
+  static bool IsUserTraffic(const net::URLRequest* request);
+
 #if defined(OS_ANDROID)
   // This function should just be used for testing purposes. A change in
   // application state can be simulated by calling this function.