SF: Populate allowGroupSwitching from DM

Currently we use allowGroupSwitching only for testing. This CL
populates its value from DisplayManager so we can use user
setting to change its value.

Bug: 161776333
Test: atest libsurfaceflinger_unittest
Change-Id: I851eaee7f86083d97204cf3553e728350c942dfe
diff --git a/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp b/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp
index 8661b6e..7ab49a9 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp
+++ b/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp
@@ -48,6 +48,13 @@
     }
 }
 
+std::string RefreshRateConfigs::Policy::toString() {
+    return base::StringPrintf("default config ID: %d, allowGroupSwitching = %d"
+                              ", primary range: [%.2f %.2f], app request range: [%.2f %.2f]",
+                              defaultConfig.value(), allowGroupSwitching, primaryRange.min,
+                              primaryRange.max, appRequestRange.min, appRequestRange.max);
+}
+
 const RefreshRate& RefreshRateConfigs::getRefreshRateForContent(
         const std::vector<LayerRequirement>& layers) const {
     std::lock_guard lock(mLock);