Fix clang-tidy warnings in aapt and aapt2.

* Add explicit keyword to conversion constructors.
* Add NOLINT(implicit) comments for implicit conversion constructors.
Bug: 28341362
* Use const reference type for read-only parameters.
Bug: 30407689
* Use const reference type to avoid unnecessary copy.
Bug: 30413862
Test: build with WITH_TIDY=1

Change-Id: Id6d21961f313a1ad92b15a37fdaa5be9e8ab48e1
diff --git a/tools/aapt2/Resource.h b/tools/aapt2/Resource.h
index 0ba0345..09a04e0 100644
--- a/tools/aapt2/Resource.h
+++ b/tools/aapt2/Resource.h
@@ -100,7 +100,7 @@
     ResourceNameRef() = default;
     ResourceNameRef(const ResourceNameRef&) = default;
     ResourceNameRef(ResourceNameRef&&) = default;
-    ResourceNameRef(const ResourceName& rhs);
+    ResourceNameRef(const ResourceName& rhs);  // NOLINT(implicit)
     ResourceNameRef(const StringPiece& p, ResourceType t, const StringPiece& e);
     ResourceNameRef& operator=(const ResourceNameRef& rhs) = default;
     ResourceNameRef& operator=(ResourceNameRef&& rhs) = default;
@@ -126,7 +126,7 @@
 
     ResourceId();
     ResourceId(const ResourceId& rhs);
-    ResourceId(uint32_t resId);
+    ResourceId(uint32_t resId);  // NOLINT(implicit)
     ResourceId(uint8_t p, uint8_t t, uint16_t e);
 
     bool isValid() const;