Fix google-explicit-constructor warnings in surfaceflinger.

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

Change-Id: I94f511c3be31dc22022db6466ee9ed0c6be2bc8e
diff --git a/services/surfaceflinger/MessageQueue.h b/services/surfaceflinger/MessageQueue.h
index 1004f4c..aed0aa9 100644
--- a/services/surfaceflinger/MessageQueue.h
+++ b/services/surfaceflinger/MessageQueue.h
@@ -69,7 +69,7 @@
         MessageQueue& mQueue;
         int32_t mEventMask;
     public:
-        Handler(MessageQueue& queue) : mQueue(queue), mEventMask(0) { }
+        explicit Handler(MessageQueue& queue) : mQueue(queue), mEventMask(0) { }
         virtual void handleMessage(const Message& message);
         void dispatchRefresh();
         void dispatchInvalidate();