Collect some histograms about signed binary downloads.

chrome/browser/download/chrome_download_manager_delegate.cc

Index: chrome/browser/download/chrome_download_manager_delegate.cc
===================================================================
--- chrome/browser/download/chrome_download_manager_delegate.cc	(revision 107068)
+++ chrome/browser/download/chrome_download_manager_delegate.cc	(working copy)
@@ -225,8 +225,28 @@
     DownloadItem* item,
     const FilePath& new_path) {
   download_history_->UpdateDownloadPath(item, new_path);
+
+#if defined(ENABLE_SAFE_BROWSING)
+  // Begin the safe browsing download protection check.
+  SafeBrowsingService* sb_service = g_browser_process->safe_browsing_service();
+  if (sb_service && sb_service->download_protection_service()) {
+    using safe_browsing::DownloadProtectionService;
+    sb_service->download_protection_service()->CheckClientDownload(
+        DownloadProtectionService::DownloadInfo::FromDownloadItem(*item),
+        base::Bind(&ChromeDownloadManagerDelegate::CheckClientDownloadDone,
+                   this));
+  }
+#else
+  // Assume safe.
+  CheckClientDownloadDone(safe_browsing::DownloadProtectionService::SAFE);
+#endif
 }
 
+void ChromeDownloadManagerDelegate::CheckClientDownloadDone(
+    safe_browsing::DownloadProtectionService::DownloadCheckResult result) {
+  // TODO(bryner): notify the user based on this result
+}
+
 void ChromeDownloadManagerDelegate::RemoveItemFromPersistentStore(
     DownloadItem* item) {
   download_history_->RemoveEntry(item);