Add SaveLayer-Draw-Restore optimization.

src/record/SkRecordOpts.h

Index: src/record/SkRecordOpts.h
diff --git a/src/record/SkRecordOpts.h b/src/record/SkRecordOpts.h
index 6db7abca611b2587b007afede4500547dff66a75..ad8c3bcfc7268cc1f0468d55baf845db16478486 100644
--- a/src/record/SkRecordOpts.h
+++ b/src/record/SkRecordOpts.h
@@ -17,6 +17,10 @@ void SkRecordOptimize(SkRecord*);
 // Turns logical no-op Save-[non-drawing command]*-Restore patterns into actual no-ops.
 void SkRecordNoopSaveRestores(SkRecord*);
 
+// For some SaveLayer-[drawing command]-Restore patterns, merge the SaveLayer's alpha into the
+// draw, and no-op the SaveLayer and Restore.
+void SkRecordNoopSaveLayerDrawRestores(SkRecord*);
+
 // Annotates PushCull commands with the relative offset of their paired PopCull.
 void SkRecordAnnotateCullingPairs(SkRecord*);