SF: Clean up Scheduler

Remove dynamic allocation for Scheduler::{Connection,ConnectionHandle},
as well as ref-counting for the latter. Also, remove dead code and make
members private.

Bug: 130554049
Test: libsurfaceflinger_unittest
Change-Id: Ibb9dc8d4cb66451a4172c852a36032bbc0a54411
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 27a119b..9536dd1 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -61,7 +61,7 @@
 public:
     ~Factory() = default;
 
-    std::unique_ptr<DispSync> createDispSync(const char*, bool, int64_t) override {
+    std::unique_ptr<DispSync> createDispSync(const char*, bool) override {
         // TODO: Use test-fixture controlled factory
         return nullptr;
     }
@@ -198,8 +198,8 @@
                 new TestableScheduler(std::move(primaryDispSync), std::move(eventControlThread),
                                       mFlinger->mRefreshRateConfigs);
 
-        mFlinger->mAppConnectionHandle = mScheduler->addConnection(std::move(appEventThread));
-        mFlinger->mSfConnectionHandle = mScheduler->addConnection(std::move(sfEventThread));
+        mFlinger->mAppConnectionHandle = mScheduler->createConnection(std::move(appEventThread));
+        mFlinger->mSfConnectionHandle = mScheduler->createConnection(std::move(sfEventThread));
 
         mFlinger->mScheduler.reset(mScheduler);
         mFlinger->mVSyncModulator.emplace(*mScheduler, mFlinger->mAppConnectionHandle,