Introduce chrome.displaySource API

extensions/browser/api/display_source/display_source_connection_delegate.cc

+// Copyright 2015 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/api/display_source/display_source_connection_delegate.h"
+
+namespace extensions {
+
+DisplaySourceConnectionDelegate::Connection::Connection() {}
+
+DisplaySourceConnectionDelegate::Connection::~Connection() {}
+
+DisplaySourceConnectionDelegate::DisplaySourceConnectionDelegate() {}
+
+DisplaySourceConnectionDelegate::~DisplaySourceConnectionDelegate() {}
+
+void DisplaySourceConnectionDelegate::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void DisplaySourceConnectionDelegate::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+}  // namespace extensions