Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: Ibdd6a210bb7ff228e3624cc319169f77aca3b51e
diff --git a/libs/hwui/AnimatorManager.cpp b/libs/hwui/AnimatorManager.cpp
index cd30b18..22947b0 100644
--- a/libs/hwui/AnimatorManager.cpp
+++ b/libs/hwui/AnimatorManager.cpp
@@ -155,7 +155,7 @@
 
 class EndActiveAnimatorsFunctor {
 public:
-    EndActiveAnimatorsFunctor(AnimationContext& context) : mContext(context) {}
+    explicit EndActiveAnimatorsFunctor(AnimationContext& context) : mContext(context) {}
 
     void operator() (BaseRenderNodeAnimator* animator) {
         animator->forceEndNow(mContext);