Throttle script request incidents to one per user.

chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc

 // 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.
 
 #include "chrome/browser/safe_browsing/incident_reporting/script_request_incident.h"
 
 #include "base/logging.h"
 #include "chrome/browser/safe_browsing/incident_reporting/incident_handler_util.h"
 #include "chrome/common/safe_browsing/csd.pb.h"
 
 namespace safe_browsing {
 
 ScriptRequestIncident::ScriptRequestIncident(
     scoped_ptr<ClientIncidentReport_IncidentData_ScriptRequestIncident>
         script_request_incident) {
   DCHECK(script_request_incident);
   DCHECK(script_request_incident->has_script_digest());
   payload()->set_allocated_script_request(script_request_incident.release());
 }
 
 ScriptRequestIncident::~ScriptRequestIncident() {
 }
 
 IncidentType ScriptRequestIncident::GetType() const {
   return IncidentType::SCRIPT_REQUEST;
 }
 
 std::string ScriptRequestIncident::GetKey() const {
-  return payload()->script_request().script_digest();
+  // Use a static key in addition to a fixed digest below to ensure that only
+  // one incident per user is reported.
+  return "script_request_incident";
 }
 
 uint32_t ScriptRequestIncident::ComputeDigest() const {
-  // Return a constant to ensure that only one incident per digest is reported.
+  // Return a constant in addition to a fixed key above to ensure that only one
+  // incident per user is reported.
   return 42;
 }
 
 }  // namespace safe_browsing