SF: Short-circuit scheduler content detection

Avoid registering, recording, partitioning, and transforming layers
for content detection in the scheduler if there is a single refresh
rate config.

Dump content detection version, and layer history stats.

Bug: 158780872
Test: No layer history on crosshatch, ARC, etc.
Test: dumpsys SurfaceFlinger --vsync
Test: libsurfaceflinger_unittest
Change-Id: Ia23a35cd6aa0cb117b19c98f5d0af8c14836430e
diff --git a/services/surfaceflinger/Scheduler/RefreshRateConfigs.h b/services/surfaceflinger/Scheduler/RefreshRateConfigs.h
index 8a51b85..4ee7ff3 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateConfigs.h
+++ b/services/surfaceflinger/Scheduler/RefreshRateConfigs.h
@@ -273,6 +273,11 @@
     RefreshRateConfigs(const std::vector<std::shared_ptr<const HWC2::Display::Config>>& configs,
                        HwcConfigIndexType currentConfigId);
 
+    // Returns whether switching configs (refresh rate or resolution) is possible.
+    // TODO(b/158780872): Consider HAL support, and skip frame rate detection if the configs only
+    // differ in resolution.
+    bool canSwitch() const { return mRefreshRates.size() > 1; }
+
     // Class to enumerate options around toggling the kernel timer on and off. We have an option
     // for no change to avoid extra calls to kernel.
     enum class KernelIdleTimerAction {