extensions: Introduce a fake ExtensionsClient implementation.

extensions/test/test_permission_message_provider.h

+// Copyright 2014 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.
+
+#ifndef EXTENSIONS_TEST_TEST_PERMISSION_MESSAGE_PROVIDER_H_
+#define EXTENSIONS_TEST_TEST_PERMISSION_MESSAGE_PROVIDER_H_
+
+#include "base/macros.h"
+#include "extensions/common/permissions/permission_message_provider.h"
+
+namespace extensions {
+
+class TestPermissionMessageProvider : public PermissionMessageProvider {
+ public:
+  TestPermissionMessageProvider();
+  virtual ~TestPermissionMessageProvider();
+
+ private:
+  virtual PermissionMessages GetPermissionMessages(

[James Cook, 2014/04/11 16:26:49]

nit: "PermissionMessageProvider implementation" above?

+      const PermissionSet* permissions,
+      Manifest::Type extension_type) const OVERRIDE;
+  virtual std::vector<base::string16> GetWarningMessages(
+      const PermissionSet* permissions,
+      Manifest::Type extension_type) const OVERRIDE;
+  virtual std::vector<base::string16> GetWarningMessagesDetails(
+      const PermissionSet* permissions,
+      Manifest::Type extension_type) const OVERRIDE;
+  virtual bool IsPrivilegeIncrease(
+      const PermissionSet* old_permissions,
+      const PermissionSet* new_permissions,
+      Manifest::Type extension_type) const OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(TestPermissionMessageProvider);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_TEST_TEST_PERMISSION_MESSAGE_PROVIDER_H_