Revert "SF: Use strong pointers to Layer when moving snapshot"

This reverts commit 5c259c0e07395b7d80a43a36d500ba6412606689.

Reason for revert: b/258572995 - performance regression

Change-Id: I7b8225fe6cf3a2dfa71c55ef213d081daa105cc3
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index e3fe7a7..8e61231 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -3974,17 +3974,14 @@
 }
 
 LayerSnapshotGuard::LayerSnapshotGuard(Layer* layer) : mLayer(layer) {
-    LOG_ALWAYS_FATAL_IF(!mLayer, "LayerSnapshotGuard received a null layer.");
-    mLayer->mLayerFE->mSnapshot = std::move(mLayer->mSnapshot);
-    LOG_ALWAYS_FATAL_IF(!mLayer->mLayerFE->mSnapshot,
-                        "LayerFE snapshot null after taking ownership from layer");
+    if (mLayer) {
+        mLayer->mLayerFE->mSnapshot = std::move(mLayer->mSnapshot);
+    }
 }
 
 LayerSnapshotGuard::~LayerSnapshotGuard() {
     if (mLayer) {
         mLayer->mSnapshot = std::move(mLayer->mLayerFE->mSnapshot);
-        LOG_ALWAYS_FATAL_IF(!mLayer->mSnapshot,
-                            "Layer snapshot null after taking ownership from LayerFE");
     }
 }