Add a new group policy to disable safe browsing for files downloaded from trusted sources.

chrome/browser/download/trusted_sources_manager.cc

Index: chrome/browser/download/trusted_sources_manager.cc
diff --git a/chrome/browser/download/trusted_sources_manager.cc b/chrome/browser/download/trusted_sources_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..67237bc2b8148aaca36175575313134291f247bd
--- /dev/null
+++ b/chrome/browser/download/trusted_sources_manager.cc
@@ -0,0 +1,21 @@
+// Copyright (c) 2017 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.
+
+#include "chrome/browser/download/trusted_sources_manager.h"
+
+#include "base/command_line.h"
+#include "chrome/common/chrome_switches.h"
+
+TrustedSourcesManager::TrustedSourcesManager() {
+  base::CommandLine* command_line(base::CommandLine::ForCurrentProcess());
+  DCHECK(command_line);
+  rules_.ParseFromString(
+      command_line->GetSwitchValueASCII(switches::kTrustedDownloadSources));
+}
+
+TrustedSourcesManager::~TrustedSourcesManager() = default;
+
+bool TrustedSourcesManager::IsFromTrustedSource(const GURL& url) const {
+  return rules_.Matches(url);
+}