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/ResourceCache.h b/libs/hwui/ResourceCache.h
index 4583c8d..3ac7864 100644
--- a/libs/hwui/ResourceCache.h
+++ b/libs/hwui/ResourceCache.h
@@ -42,7 +42,7 @@
 class ResourceReference {
 public:
 
-    ResourceReference(ResourceType type) {
+    explicit ResourceReference(ResourceType type) {
         refCount = 0; destroyed = false; resourceType = type;
     }