Support toggling layer caching at runtime

The use-case for this is dynamically enabling and disabling layer
caching when a bad layer state is encountered that is difficult to
reproduce.

Bug: 187448777
Test: adb shell service call SurfaceFlinger 1040 i32 1
Test: libcompositionengine_test
Change-Id: Id441a0894ff5a4c654db9fd706ceb1c0d1c343f0
Merged-In: Id441a0894ff5a4c654db9fd706ceb1c0d1c343f0
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 297e687..796fe7d 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -55,18 +55,6 @@
 
 namespace impl {
 
-Output::Output() {
-    const bool enableLayerCaching = [] {
-        const bool enable =
-                android::sysprop::SurfaceFlingerProperties::enable_layer_caching().value_or(false);
-        return base::GetBoolProperty(std::string("debug.sf.enable_layer_caching"), enable);
-    }();
-
-    if (enableLayerCaching) {
-        mPlanner = std::make_unique<planner::Planner>();
-    }
-}
-
 namespace {
 
 template <typename T>
@@ -135,6 +123,21 @@
     dirtyEntireOutput();
 }
 
+void Output::setLayerCachingEnabled(bool enabled) {
+    if (enabled == (mPlanner != nullptr)) {
+        return;
+    }
+
+    if (enabled) {
+        mPlanner = std::make_unique<planner::Planner>();
+        if (mRenderSurface) {
+            mPlanner->setDisplaySize(mRenderSurface->getSize());
+        }
+    } else {
+        mPlanner.reset();
+    }
+}
+
 void Output::setProjection(ui::Rotation orientation, const Rect& layerStackSpaceRect,
                            const Rect& orientedDisplaySpaceRect) {
     auto& outputState = editState();