[Downloads] Move client guid for AV scanning of downloaded files to chrome/

content/public/browser/download_manager_delegate.h

Index: content/public/browser/download_manager_delegate.h
diff --git a/content/public/browser/download_manager_delegate.h b/content/public/browser/download_manager_delegate.h
index 98bad436dee01a714e0df391ac41dacad7e844f4..89be2df185542e3d854c27e556b229e363683197 100644
--- a/content/public/browser/download_manager_delegate.h
+++ b/content/public/browser/download_manager_delegate.h
@@ -129,6 +129,12 @@ class CONTENT_EXPORT DownloadManagerDelegate {
       DownloadItem* download,
       const CheckForFileExistenceCallback& callback) {}
 
+  // Return a GUID string used for identifying the application to the
+  // system AV function for scanning downloaded files. If an empty
+  // or invalid GUID string is returned, no client identification
+  // will be given to the AV function.
+  virtual std::string ApplicationClientIdForFileScanning() const;
+
  protected:
   virtual ~DownloadManagerDelegate();
 };