The optional Malware Details also collects HTTP cache information. See design...

chrome/browser/safe_browsing/safe_browsing_blocking_page.cc

 // Copyright (c) 2011 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.
 //
 // Implementation of the SafeBrowsingBlockingPage class.
 
 #include "chrome/browser/safe_browsing/safe_browsing_blocking_page.h"
 
 #include <string>
 
@@ skipping 129 matching lines @@
   // Start computing malware details. They will be sent only
   // if the user opts-in on the blocking page later.
   // If there's more than one malicious resources, it means the user
   // clicked through the first warning, so we don't prepare additional
   // reports.
   if (unsafe_resources.size() == 1 &&
       unsafe_resources[0].threat_type == SafeBrowsingService::URL_MALWARE &&
       malware_details_ == NULL &&
       CanShowMalwareDetailsOption()) {
     malware_details_ = MalwareDetails::NewMalwareDetails(
-        tab(), unsafe_resources[0]);
+        sb_service_, tab(), unsafe_resources[0]);
   }
 }
 
 bool SafeBrowsingBlockingPage::CanShowMalwareDetailsOption() {
   return (!tab()->profile()->IsOffTheRecord() &&
           tab()->GetURL().SchemeIs(chrome::kHttpScheme));
 }
 
 SafeBrowsingBlockingPage::~SafeBrowsingBlockingPage() {
 }
@@ skipping 437 matching lines @@
 void SafeBrowsingBlockingPage::FinishMalwareDetails() {
   if (malware_details_ == NULL)
     return;  // Not all interstitials have malware details (eg phishing).
 
   const PrefService::Preference* pref =
       tab()->profile()->GetPrefs()->FindPreference(
           prefs::kSafeBrowsingReportingEnabled);
 
   bool value;
   if (pref && pref->GetValue()->GetAsBoolean(&value) && value) {
-    // Give the details object to the service class, so it can send it.
+    // Finish the malware details collection, send it over.
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         NewRunnableMethod(
-            sb_service_, &SafeBrowsingService::ReportMalwareDetails,
-            malware_details_));
+            malware_details_.get(), &MalwareDetails::FinishCollection));
   }
 }
 
 // static
 void SafeBrowsingBlockingPage::NotifySafeBrowsingService(
     SafeBrowsingService* sb_service,
     const UnsafeResourceList& unsafe_resources,
     bool proceed) {
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
@@ skipping 45 matching lines @@
   UnsafeResourceMap* unsafe_resource_map = GetUnsafeResourcesMap();
   (*unsafe_resource_map)[tab_contents].push_back(unsafe_resource);
 }
 
 // static
 bool SafeBrowsingBlockingPage::IsMainPage(
     const UnsafeResourceList& unsafe_resources) {
   return unsafe_resources.size() == 1 &&
          unsafe_resources[0].resource_type == ResourceType::MAIN_FRAME;
 }