Fix google-explicit-constructor warnings in minikin

* Add explicit keyword to conversion constructors,
  or add NOLINT(implicit) for implicit converters.
Bug: 28341362
Test: build with WITH_TIDY=1

Change-Id: I0c7b90f9bb953a9f2e4f0fb2032fa65ac604b9ca

include/minikin/FontFamily.h

@@ -37,7 +37,7 @@ class FontStyle {
 public:
     FontStyle() : FontStyle(0 /* variant */, 4 /* weight */, false /* italic */) {}
     FontStyle(int weight, bool italic) : FontStyle(0 /* variant */, weight, italic) {}
-    FontStyle(uint32_t langListId)
+    FontStyle(uint32_t langListId)  // NOLINT(implicit)
             : FontStyle(langListId, 0 /* variant */, 4 /* weight */, false /* italic */) {}
 
     FontStyle(int variant, int weight, bool italic);
@@ -102,7 +102,7 @@ class FontFamily : public MinikinRefCounted {
 public:
     FontFamily();
 
-    FontFamily(int variant);
+    explicit FontFamily(int variant);
 
     FontFamily(uint32_t langId, int variant)
         : mLangId(langId),

include/minikin/MinikinFont.h

@@ -33,7 +33,7 @@ namespace minikin {
 class HyphenEdit {
 public:
     HyphenEdit() : hyphen(0) { }
-    HyphenEdit(uint32_t hyphenInt) : hyphen(hyphenInt) { }
+    HyphenEdit(uint32_t hyphenInt) : hyphen(hyphenInt) { }  // NOLINT(implicit)
     bool hasHyphen() const { return hyphen != 0; }
     bool operator==(const HyphenEdit &other) const { return hyphen == other.hyphen; }
 private:
@@ -99,7 +99,7 @@ typedef void (*MinikinDestroyFunc) (void* data);
 
 class MinikinFont : public MinikinRefCounted {
 public:
-    MinikinFont(int32_t uniqueId) : mUniqueId(uniqueId) {}
+    explicit MinikinFont(int32_t uniqueId) : mUniqueId(uniqueId) {}
 
     virtual ~MinikinFont();
 

include/minikin/MinikinRefCounted.h

@@ -42,7 +42,7 @@ private:
 template <typename T>
 class MinikinAutoUnref {
 public:
-    MinikinAutoUnref(T* obj) : mObj(obj) {
+    explicit MinikinAutoUnref(T* obj) : mObj(obj) {
     }
     ~MinikinAutoUnref() {
         mObj->Unref();

libs/minikin/FontLanguage.h

@@ -98,7 +98,7 @@ private:
 // An immutable list of languages.
 class FontLanguages {
 public:
-    FontLanguages(std::vector<FontLanguage>&& languages);
+    explicit FontLanguages(std::vector<FontLanguage>&& languages);
     FontLanguages() : mUnionOfSubScriptBits(0), mIsAllTheSameLanguage(false) {}
     FontLanguages(FontLanguages&&) = default;
 

libs/minikin/MinikinInternal.h

@@ -52,7 +52,7 @@ class HbBlob {
 public:
     // Takes ownership of hb_blob_t object, caller is no longer
     // responsible for calling hb_blob_destroy().
-    HbBlob(hb_blob_t* blob) : mBlob(blob) {
+    explicit HbBlob(hb_blob_t* blob) : mBlob(blob) {
     }
 
     ~HbBlob() {