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/aapt/pseudolocalize.h b/tools/aapt/pseudolocalize.h
index 1faecd1..9bb1fd8 100644
--- a/tools/aapt/pseudolocalize.h
+++ b/tools/aapt/pseudolocalize.h
@@ -43,7 +43,7 @@
 
 class Pseudolocalizer {
  public:
-  Pseudolocalizer(PseudolocalizationMethod m);
+  explicit Pseudolocalizer(PseudolocalizationMethod m);
   ~Pseudolocalizer() { if (mImpl) delete mImpl; }
   void setMethod(PseudolocalizationMethod m);
   String16 start() { return mImpl->start(); }