Start to unify signatures: return bool

Change-Id: If4a8e06f3a176697e3f5136dfc7ab1fbb347da70
Bug: skia:8937
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/205120
Reviewed-by: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/src/utils/SkShadowUtils.cpp b/src/utils/SkShadowUtils.cpp
index 41e8180..dd56b0e 100644
--- a/src/utils/SkShadowUtils.cpp
+++ b/src/utils/SkShadowUtils.cpp
@@ -47,8 +47,9 @@
 
 protected:
     void flatten(SkWriteBuffer&) const override {}
-    void onAppendStages(const SkStageRec& rec, bool shaderIsOpaque) const override {
+    bool onAppendStages(const SkStageRec& rec, bool shaderIsOpaque) const override {
         rec.fPipeline->append(SkRasterPipeline::gauss_a_to_rgba);
+        return true;
     }
 private:
     SK_FLATTENABLE_HOOKS(SkGaussianColorFilter)