Make blur regions alpha depend on layer alpha

Bug: 183109337
Test: m && flash && check blur region alpha animating
Change-Id: I17032051909c12aab60225a080b7431e0b35814a
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 3a45c94..a2a0da1 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -1192,7 +1192,7 @@
     float mEffectiveShadowRadius = 0.f;
 
     // A list of regions on this layer that should have blurs.
-    const std::vector<BlurRegion>& getBlurRegions() const;
+    const std::vector<BlurRegion> getBlurRegions() const;
 };
 
 std::ostream& operator<<(std::ostream& stream, const Layer::FrameRate& rate);