extensions: Introduce a fake ExtensionsClient implementation.

extensions/test/test_permissions_provider.cc

+// 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.
+
+#include "extensions/test/test_permissions_provider.h"
+
+namespace extensions {
+
+TestPermissionsProvider::TestPermissionsProvider() {}
+
+TestPermissionsProvider::~TestPermissionsProvider() {}
+
+std::vector<APIPermissionInfo*> TestPermissionsProvider::GetAllPermissions()
+    const {
+  // TODO(tfarina): This needs to have a "real" implementation, otherwise
+  // some tests under extensions_unittests will fail. http://crbug.com/348066
+  std::vector<APIPermissionInfo*> permissions;
+  return permissions;
+}
+
+std::vector<PermissionsProvider::AliasInfo>
+TestPermissionsProvider::GetAllAliases() const {
+  std::vector<PermissionsProvider::AliasInfo> aliases;
+  return aliases;
+}
+
+}  // namespace extensions