Add display manager instance which hands relevant information to emugl layer

external/android-emugl/host/libs/libOpenglRender/DisplayManager.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2016 Simon Fels <morphis@gravedo.de>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "DisplayManager.h"
+
+namespace {
+std::shared_ptr<DisplayManager> display_mgr;
+
+class NullDisplayManager : public DisplayManager {
+public:
+    DisplayInfo display_info() const override {
+        return {1280, 720};
+    }
+};
+}
+
+DisplayManager::~DisplayManager() {
+}
+
+std::shared_ptr<DisplayManager> DisplayManager::get() {
+    if (!display_mgr)
+        display_mgr = std::make_shared<NullDisplayManager>();
+    return display_mgr;
+}
+
+void registerDisplayManager(const std::shared_ptr<DisplayManager> &mgr) {
+    display_mgr = mgr;
+}