Remove forward-decleration of SkiaDisplayList

Enables DisplayList to be a wrapper around SkiaDisplayList
instead of a type-alias by having the full include of
SkiaDisplayList available

Test: builds
Change-Id: Ie906e6288530134840bee81af3a89871ed6a7d25
diff --git a/libs/hwui/tests/microbench/RenderNodeBench.cpp b/libs/hwui/tests/microbench/RenderNodeBench.cpp
index 011939a..618988f 100644
--- a/libs/hwui/tests/microbench/RenderNodeBench.cpp
+++ b/libs/hwui/tests/microbench/RenderNodeBench.cpp
@@ -16,6 +16,7 @@
 
 #include <benchmark/benchmark.h>
 
+#include "hwui/Canvas.h"
 #include "RenderNode.h"
 
 using namespace android;