SF: Clean up emitting of mode change event

Clarify the special case of emitting despite the unchanged mode. Rename
functions and state for consistency with DisplayModeRequest::emitEvent.
Remove Cycle parameters for which the argument is always Cycle::Render.

This does not change behavior.

Bug: 255635821
Flag: EXEMPT refactor
Test: SchedulerTest.emitModeChangeEvent
Change-Id: I99debb33ba84dff707d6da0a92dacc4e275fc5ce
diff --git a/services/surfaceflinger/Scheduler/RefreshRateSelector.h b/services/surfaceflinger/Scheduler/RefreshRateSelector.h
index 998b1b8..a398c01 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateSelector.h
+++ b/services/surfaceflinger/Scheduler/RefreshRateSelector.h
@@ -210,6 +210,8 @@
         // within the timeout of DisplayPowerTimer.
         bool powerOnImminent = false;
 
+        bool shouldEmitEvent() const { return !idle; }
+
         bool operator==(GlobalSignals other) const {
             return touch == other.touch && idle == other.idle &&
                     powerOnImminent == other.powerOnImminent;