Throttle script request incidents to one per user.

chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc

Index: chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc
diff --git a/chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc b/chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc
index 6aa4598083b99c2ecf8fbd7af8e99663866e84f5..74a6ca323d0e3b0c3176f92056e51050d07d3804 100644
--- a/chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/script_request_incident.cc
@@ -26,11 +26,14 @@ IncidentType ScriptRequestIncident::GetType() const {
 }
 
 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;
 }