SF: Adding tests to Scheduler class.

This is part of go/surface-flinger-scheduler project.

Test: SF tests pass.
Bug: 113612090
Change-Id: I3ef187d5b79f45c9e3962e1b2316f17b4813a2c7
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index caccd6f..8efbff4 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -52,7 +52,7 @@
     };
 
     Scheduler() = default;
-    ~Scheduler() = default;
+    virtual ~Scheduler();
 
     /** Creates an EventThread connection. */
     sp<ConnectionHandle> createConnection(
@@ -77,6 +77,12 @@
     // Offers ability to modify phase offset in the event thread.
     void setPhaseOffset(const sp<ConnectionHandle>& handle, nsecs_t phaseOffset);
 
+protected:
+    virtual std::unique_ptr<EventThread> makeEventThread(
+            const char* connectionName, DispSync* dispSync, int64_t phaseOffsetNs,
+            impl::EventThread::ResyncWithRateLimitCallback resyncCallback,
+            impl::EventThread::InterceptVSyncsCallback interceptCallback);
+
 private:
     static std::atomic<int64_t> sNextId;
     std::unordered_map<int64_t, std::unique_ptr<Connection>> mConnections;