PreloadCheck class for extension pre-install checks

extensions/browser/policy_check.cc

+// Copyright 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 "extensions/browser/policy_check.h"
+
+#include "content/public/browser/browser_context.h"
+#include "extensions/browser/extension_system.h"
+#include "extensions/browser/management_policy.h"
+
+namespace extensions {
+
+PolicyCheck::PolicyCheck(content::BrowserContext* context,

[Devlin, 2017/03/16 01:42:44]

nit: Rather than pass in the context here, maybe pass in the management policy
directly?  Saves a bit of mocking in the test, and keeps the class a bit more
narrow.

[michaelpg, 2017/03/17 02:34:26]

I'll keep this in mind in case it becomes an issue later. But at a certain point
we might as well just inline the check (which is what I'm trying to avoid,
because it gets untenable as the number of one-off checks grows).

+                         scoped_refptr<const Extension> extension)
+    : PreloadCheck(extension), context_(context) {}
+
+PolicyCheck::~PolicyCheck() {}
+
+void PolicyCheck::Start(ResultCallback callback) {
+  Errors errors;
+  if (!ExtensionSystem::Get(context_)->management_policy()->UserMayLoad(
+          extension(), &error_)) {
+    DCHECK(!error_.empty());
+    errors.insert(DISALLOWED_BY_POLICY);
+  }
+  std::move(callback).Run(errors);
+}
+
+base::string16 PolicyCheck::GetErrorMessage() const {
+  return error_;
+}
+
+}  // namespace extensions