SF: Fully disable content detection if opted out

Layer history was created but not recorded/traversed on devices without
refresh rate switching. ag/9549429 destroys stale history on traversal,
so the LayerInfo records were leaked.

Bug: 144363590
Test: Layer history is not created on crosshatch
Change-Id: I45ebc7c4f8447b2bc2bfb1af01325d562b4afed1
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index ae6aa89..40c00c4 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -21,6 +21,7 @@
 
 #include "Scheduler/DispSync.h"
 #include "Scheduler/EventThread.h"
+#include "Scheduler/LayerHistory.h"
 #include "Scheduler/Scheduler.h"
 
 namespace android {
@@ -28,18 +29,26 @@
 class TestableScheduler : public Scheduler {
 public:
     explicit TestableScheduler(const scheduler::RefreshRateConfigs& configs)
-          : Scheduler([](bool) {}, configs) {}
+          : Scheduler([](bool) {}, configs) {
+        mLayerHistory.emplace();
+    }
 
     TestableScheduler(std::unique_ptr<DispSync> primaryDispSync,
                       std::unique_ptr<EventControlThread> eventControlThread,
                       const scheduler::RefreshRateConfigs& configs)
-          : Scheduler(std::move(primaryDispSync), std::move(eventControlThread), configs) {}
+          : Scheduler(std::move(primaryDispSync), std::move(eventControlThread), configs) {
+        mLayerHistory.emplace();
+    }
 
     // Used to inject mock event thread.
     ConnectionHandle createConnection(std::unique_ptr<EventThread> eventThread) {
         return Scheduler::createConnection(std::move(eventThread));
     }
 
+    size_t layerHistorySize() const NO_THREAD_SAFETY_ANALYSIS {
+        return mLayerHistory->mLayerInfos.size();
+    }
+
     /* ------------------------------------------------------------------------
      * Read-write access to private data to set up preconditions and assert
      * post-conditions.