Fix/suppress aapt/aapt2 google-explicit-constructor warnings

* Add explicit to conversion constructors/operators
* Use NOLINT or NOLINTNEXTLINE to suppress warnings on intended converters

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: Ie02101ea7c422e8add535c111a30a2f21ead0ace
diff --git a/tools/aapt2/link/XmlCompatVersioner.h b/tools/aapt2/link/XmlCompatVersioner.h
index 099e23c..9980618 100644
--- a/tools/aapt2/link/XmlCompatVersioner.h
+++ b/tools/aapt2/link/XmlCompatVersioner.h
@@ -55,7 +55,7 @@
  public:
   using Rules = std::unordered_map<ResourceId, std::unique_ptr<IDegradeRule>>;
 
-  XmlCompatVersioner(const Rules* rules);
+  explicit XmlCompatVersioner(const Rules* rules);
 
   std::vector<std::unique_ptr<xml::XmlResource>> Process(IAaptContext* context,
                                                          xml::XmlResource* doc,
@@ -83,7 +83,7 @@
 
 class DegradeToManyRule : public IDegradeRule {
  public:
-  DegradeToManyRule(std::vector<ReplacementAttr> attrs);
+  explicit DegradeToManyRule(std::vector<ReplacementAttr> attrs);
   virtual ~DegradeToManyRule() = default;
 
   std::vector<DegradeResult> Degrade(const xml::Element& src_el, const xml::Attribute& src_attr,