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/EventControlThread.h b/services/surfaceflinger/EventControlThread.h
index be6c53a..9368db6 100644
--- a/services/surfaceflinger/EventControlThread.h
+++ b/services/surfaceflinger/EventControlThread.h
@@ -29,7 +29,7 @@
 class EventControlThread: public Thread {
 public:
 
-    EventControlThread(const sp<SurfaceFlinger>& flinger);
+    explicit EventControlThread(const sp<SurfaceFlinger>& flinger);
     virtual ~EventControlThread() {}
 
     void setVsyncEnabled(bool enabled);