Add missing getter & improve docs

Also fix SkiaDisplayList::getUsedSize()

Bug: 120865963
Test: atest android.uirendering.cts.testclasses.RenderNodeTests
Change-Id: I3cdbd8d330da9a00367199087c9ae1e0a2cacf46
diff --git a/libs/hwui/RenderProperties.h b/libs/hwui/RenderProperties.h
index 04379ae..ddb7e4e 100644
--- a/libs/hwui/RenderProperties.h
+++ b/libs/hwui/RenderProperties.h
@@ -98,15 +98,15 @@
 
     LayerProperties& operator=(const LayerProperties& other);
 
+    // Strongly recommend using effectiveLayerType instead
+    LayerType type() const { return mType; }
+
 private:
     LayerProperties();
     ~LayerProperties();
     void reset();
     bool setColorFilter(SkColorFilter* filter);
 
-    // Private since external users should go through properties().effectiveLayerType()
-    LayerType type() const { return mType; }
-
     friend class RenderProperties;
 
     LayerType mType = LayerType::None;