Adding a DownloadRestrictions group policy.

chrome/browser/download/chrome_download_manager_delegate.h

Index: chrome/browser/download/chrome_download_manager_delegate.h
diff --git a/chrome/browser/download/chrome_download_manager_delegate.h b/chrome/browser/download/chrome_download_manager_delegate.h
index 1091d3ed80f501c8c843ca7287c5fb12c581284f..abe175a3b3c212f5183d2a26da2827047ac3f109 100644
--- a/chrome/browser/download/chrome_download_manager_delegate.h
+++ b/chrome/browser/download/chrome_download_manager_delegate.h
@@ -8,6 +8,8 @@
 #include <stdint.h>
 
 #include <memory>
+#include <string>
+#include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
@@ -84,6 +86,7 @@ class ChromeDownloadManagerDelegate
       content::DownloadItem* download,
       const content::CheckForFileExistenceCallback& callback) override;
   std::string ApplicationClientIdForFileScanning() const override;
+  bool ShouldBlockAllDownloads() const override;
 
   // Opens a download using the platform handler. DownloadItem::OpenDownload,
   // which ends up being handled by OpenDownload(), will open a download in the
@@ -157,6 +160,10 @@ class ChromeDownloadManagerDelegate
   // Returns true if |path| should open in the browser.
   bool IsOpenInBrowserPreferreredForFile(const base::FilePath& path);
 
+  // Return true if the downloaded file should be blocked on on the current pref
+  // and |danger_type|.
+  bool ShouldBlockFile(content::DownloadDangerType danger_type) const;
+
   Profile* profile_;
   uint32_t next_download_id_;
   IdCallbackVector id_callbacks_;