Improve dumping of display list memory usage

The first step of improving is measuring. So measure better.

Bug: 138856108
Test: dump
Change-Id: I076b904a1f0dfb209622c76bcb8778a10cd2b7db
diff --git a/libs/hwui/RenderNode.h b/libs/hwui/RenderNode.h
index c6db7f1..d55e5b0 100644
--- a/libs/hwui/RenderNode.h
+++ b/libs/hwui/RenderNode.h
@@ -102,7 +102,8 @@
     ANDROID_API void setStagingDisplayList(DisplayList* newData);
 
     ANDROID_API void output();
-    ANDROID_API int getDebugSize();
+    ANDROID_API int getUsageSize();
+    ANDROID_API int getAllocatedSize();
 
     bool isRenderable() const { return mDisplayList && !mDisplayList->isEmpty(); }