Fix google-explicit-constructor warnings in libs/hwui.

* Add explicit keyword to conversion constructors,
  or add NOLINT for implicit converters.
Bug: 28341362
Test: build with WITH_TIDY=1

Change-Id: Id8ca42433a4fc3652e4cb13787c4cb169f20d9a9
diff --git a/libs/hwui/PropertyValuesAnimatorSet.h b/libs/hwui/PropertyValuesAnimatorSet.h
index c7ae7c0..602fd91 100644
--- a/libs/hwui/PropertyValuesAnimatorSet.h
+++ b/libs/hwui/PropertyValuesAnimatorSet.h
@@ -73,7 +73,7 @@
 
 class PropertyAnimatorSetListener : public AnimationListener {
 public:
-    PropertyAnimatorSetListener(PropertyValuesAnimatorSet* set) : mSet(set) {}
+    explicit PropertyAnimatorSetListener(PropertyValuesAnimatorSet* set) : mSet(set) {}
     virtual void onAnimationFinished(BaseRenderNodeAnimator* animator) override;
 
 private: