Add simple fake for native service manager.

Reusing the existing binder-based native service manager has
proved problematic in host/test environments.

So as a workaround, this commit creates a IServiceManager native
implementation that can be communicated with directly.

Bug: 147595993
Test: m fakeservicemanager_test; fakeservicemanager_test
Change-Id: Icfa6f2fd314bd5a7b3d5e8a064b487f92b99b133
diff --git a/libs/fakeservicemanager/ServiceManager.h b/libs/fakeservicemanager/ServiceManager.h
new file mode 100644
index 0000000..62311d4
--- /dev/null
+++ b/libs/fakeservicemanager/ServiceManager.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <binder/IServiceManager.h>
+
+#include <map>
+
+namespace android {
+
+/**
+ * A local host simple implementation of IServiceManager, that does not
+ * communicate over binder.
+*/
+class ServiceManager : public IServiceManager {
+public:
+    ServiceManager();
+
+    /**
+     * Equivalent of checkService.
+     */
+    sp<IBinder> getService( const String16& name) const override;
+
+    /**
+     * Retrieve an existing service, non-blocking.
+     */
+    sp<IBinder> checkService( const String16& name) const override;
+
+    /**
+     * Register a service.
+     */
+    status_t addService(const String16& name, const sp<IBinder>& service,
+                        bool allowIsolated = false,
+                        int dumpsysFlags = DUMP_FLAG_PRIORITY_DEFAULT) override;
+
+    /**
+     * Return list of all existing services.
+     */
+    Vector<String16> listServices(int dumpsysFlags = 0) override;
+
+    IBinder* onAsBinder() override;
+
+    /**
+     * Effectively no-oped in this implementation - equivalent to checkService.
+     */
+    sp<IBinder> waitForService(const String16& name) override;
+
+    /**
+     * Check if a service is declared (e.g. VINTF manifest).
+     *
+     * If this returns true, waitForService should always be able to return the
+     * service.
+     */
+     bool isDeclared(const String16& name) override;
+
+private:
+    std::map<String16, sp<IBinder>> mNameToService;
+};
+
+}  // namespace android