Adding a DownloadRestrictions group policy.

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 2c91638b118fddf902bb49f7eb12853cfc9f8481..116bf4f61ef9ca1f6db820d332d1a634f9f70264 100644
--- a/content/public/browser/download_manager_delegate.h
+++ b/content/public/browser/download_manager_delegate.h
@@ -7,6 +7,8 @@
 
 #include <stdint.h>
 
+#include <string>
+
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ -150,6 +152,9 @@ class CONTENT_EXPORT DownloadManagerDelegate {
   // This GUID is only used on Windows.
   virtual std::string ApplicationClientIdForFileScanning() const;
 
+  // Identifie whether all downloads should be blocked, e.g., by group policy.
+  virtual bool ShouldBlockAllDownloads() const;
+
  protected:
   virtual ~DownloadManagerDelegate();
 };