Don't store empty objects on SF traces

Proto3 doesn't store default values for object, however, it stored the
object start-end tags if an empty object was created.

Do not create objects when they are empty

Test: Flash a device. Record SF trace. Open them in the new winscope
version with "display defaults" unchecked. Check if there are no empty
objects

Change-Id: I3f48047e43e9c62c572d5b83e63a0f96527ef146
diff --git a/services/surfaceflinger/LayerProtoHelper.h b/services/surfaceflinger/LayerProtoHelper.h
index 6df5aea..dca9a5e 100644
--- a/services/surfaceflinger/LayerProtoHelper.h
+++ b/services/surfaceflinger/LayerProtoHelper.h
@@ -26,12 +26,18 @@
 namespace surfaceflinger {
 class LayerProtoHelper {
 public:
-    static void writeToProto(const Rect& rect, RectProto* rectProto);
-    static void writeToProto(const FloatRect& rect, FloatRectProto* rectProto);
-    static void writeToProto(const Region& region, RegionProto* regionProto);
-    static void writeToProto(const half4 color, ColorProto* colorProto);
+    static void writePositionToProto(const float x, const float y,
+                                     std::function<PositionProto*()> getPositionProto);
+    static void writeSizeToProto(const uint32_t w, const uint32_t h,
+                                 std::function<SizeProto*()> getSizeProto);
+    static void writeToProto(const Rect& rect, std::function<RectProto*()> getRectProto);
+    static void writeToProto(const FloatRect& rect,
+                             std::function<FloatRectProto*()> getFloatRectProto);
+    static void writeToProto(const Region& region, std::function<RegionProto*()> getRegionProto);
+    static void writeToProto(const half4 color, std::function<ColorProto*()> getColorProto);
     static void writeToProto(const ui::Transform& transform, TransformProto* transformProto);
-    static void writeToProto(const sp<GraphicBuffer>& buffer, ActiveBufferProto* activeBufferProto);
+    static void writeToProto(const sp<GraphicBuffer>& buffer,
+                             std::function<ActiveBufferProto*()> getActiveBufferProto);
 };
 
 } // namespace surfaceflinger