SF: Move toggleKernelIdleTimer to DMC

Remove a special case for the default display by tracking the enabled
state per display.

Bug: 241285876
Bug: 355424160
Flag: EXEMPT refactor
Test: presubmit
Change-Id: Ife697e9f31bdf833910132fb0a71918b29c350eb
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 8b71f3b..b9e9f44 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -707,22 +707,13 @@
     // ICEPowerCallback overrides:
     void notifyCpuLoadUp() override;
 
-    // Toggles the kernel idle timer on or off depending the policy decisions around refresh rates.
-    void toggleKernelIdleTimer() REQUIRES(mStateLock);
-
     using KernelIdleTimerController = scheduler::RefreshRateSelector::KernelIdleTimerController;
 
     // Get the controller and timeout that will help decide how the kernel idle timer will be
     // configured and what value to use as the timeout.
     std::pair<std::optional<KernelIdleTimerController>, std::chrono::milliseconds>
             getKernelIdleTimerProperties(PhysicalDisplayId) REQUIRES(mStateLock);
-    // Updates the kernel idle timer either through HWC or through sysprop
-    // depending on which controller is provided
-    void updateKernelIdleTimer(std::chrono::milliseconds timeoutMs, KernelIdleTimerController,
-                               PhysicalDisplayId) REQUIRES(mStateLock);
-    // Keeps track of whether the kernel idle timer is currently enabled, so we don't have to
-    // make calls to sys prop each time.
-    bool mKernelIdleTimerEnabled = false;
+
     // Show spinner with refresh rate overlay
     bool mRefreshRateOverlaySpinner = false;
     // Show render rate with refresh rate overlay