Fix google-explicit-constructor warnings in frameworks/base

* Add explicit keyword to conversion constructors.
* Add NOLINT to implicit conversion constructors.

Bug: 28341362
Test: build with clang-tidy
Change-Id: Ie4d37072ab57d1662d18db4de1c8577247f43337
diff --git a/libs/hwui/thread/Barrier.h b/libs/hwui/thread/Barrier.h
index 6cb23e5..bf10704 100644
--- a/libs/hwui/thread/Barrier.h
+++ b/libs/hwui/thread/Barrier.h
@@ -24,7 +24,7 @@
 
 class Barrier {
 public:
-    Barrier(Condition::WakeUpType type = Condition::WAKE_UP_ALL) : mType(type), mOpened(false) { }
+    explicit Barrier(Condition::WakeUpType type = Condition::WAKE_UP_ALL) : mType(type), mOpened(false) { }
     ~Barrier() { }
 
     void open() {