SF: Add test for emitting of mode change event

Also, remove the trivial SchedulerTest.dispatchCachedReportedMode, and
clean up related tests.

Bug: 255635821
Flag: TEST_ONLY
Test: SchedulerTest.emitModeChangeEvent
Change-Id: Id380776438d93f701f27fc5887e9b99064d32d0e
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 0814e3d..b272cf1 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -176,6 +176,11 @@
         mPolicy.idleTimer = globalSignals.idle ? TimerState::Expired : TimerState::Reset;
     }
 
+    using Scheduler::TimerState;
+
+    using Scheduler::idleTimerCallback;
+    using Scheduler::touchTimerCallback;
+
     void setContentRequirements(std::vector<RefreshRateSelector::LayerRequirement> layers) {
         std::lock_guard<std::mutex> lock(mPolicyLock);
         mPolicy.contentRequirements = std::move(layers);
@@ -188,15 +193,7 @@
         return Scheduler::chooseDisplayModes();
     }
 
-    void dispatchCachedReportedMode() {
-        std::lock_guard<std::mutex> lock(mPolicyLock);
-        Scheduler::dispatchCachedReportedMode();
-    }
-
-    void clearCachedReportedMode() {
-        std::lock_guard<std::mutex> lock(mPolicyLock);
-        mPolicy.cachedModeChangedParams.reset();
-    }
+    using Scheduler::onPrimaryDisplayModeChanged;
 
     void setInitialHwVsyncEnabled(PhysicalDisplayId id, bool enabled) {
         auto schedule = getVsyncSchedule(id);