Fix/suppress google-explicit-constructor warnings

* Add explicit to conversion constructors/operators

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: Iac8f3aa14cd04861f6bcbab56b0dfc28c9a89e53
diff --git a/libs/input/tests/TestHelpers.h b/libs/input/tests/TestHelpers.h
index fe87bb9..343d81f 100644
--- a/libs/input/tests/TestHelpers.h
+++ b/libs/input/tests/TestHelpers.h
@@ -62,7 +62,7 @@
     int mDelayMillis;
 
 public:
-    DelayedTask(int delayMillis) : mDelayMillis(delayMillis) { }
+    explicit DelayedTask(int delayMillis) : mDelayMillis(delayMillis) { }
 
 protected:
     virtual ~DelayedTask() { }