Remove CSD token from WebProtect

Due to product decisions, this field should not be included.

Bug: 1062298
Change-Id: I46986aec184f61b9af18a6debabd356cbebb9719
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2107713Reviewed-by: Bettina Dea <bdea@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751127}

chrome/browser/safe_browsing/download_protection/deep_scanning_request.cc

@@ -192,8 +192,6 @@ void DeepScanningRequest::Start() {
     MalwareDeepScanningClientRequest malware_request;
     malware_request.set_population(
         MalwareDeepScanningClientRequest::POPULATION_TITANIUM);
-    malware_request.set_download_token(
-        DownloadProtectionService::GetDownloadPingToken(item_));
     request->set_request_malware_scan(std::move(malware_request));
   } else if (trigger_ == DeepScanTrigger::TRIGGER_POLICY) {
     policy::DMToken dm_token = GetDMToken(profile);
@@ -215,8 +213,6 @@ void DeepScanningRequest::Start() {
       MalwareDeepScanningClientRequest malware_request;
       malware_request.set_population(
           MalwareDeepScanningClientRequest::POPULATION_ENTERPRISE);
-      malware_request.set_download_token(
-          DownloadProtectionService::GetDownloadPingToken(item_));
       request->set_request_malware_scan(std::move(malware_request));
     }
   }

components/safe_browsing/content/web_ui/safe_browsing_ui.cc

@@ -1313,9 +1313,6 @@ std::string SerializeDeepScanningRequest(
         break;
     }
 
-    malware_request.SetStringKey(
-        "download_token", request.malware_scan_request().download_token());
-
     request_dict.SetKey("malware_scan_request", std::move(malware_request));
   }
 

components/safe_browsing/core/proto/webprotect.proto

@@ -18,8 +18,7 @@ message MalwareDeepScanningClientRequest {
   // Identifies the type of client.
   optional Population population = 1;
 
-  // The download token from the original ClientDownloadResponse.
-  optional string download_token = 2;
+  reserved 2;
 }
 
 // DLP-specific scanning information.