ART: Fix tidy warnings

Switch to char versions of find variants.

Add "explicit" constructor variants or refactor and
remove defaults.

Use const references.

Bug: 32619234
Test: m test-art-host
Change-Id: I970cc2f47d6cf8f0c74104b994b075b2fafb3d45
diff --git a/cmdline/cmdline.h b/cmdline/cmdline.h
index dec9c83..6e042c3 100644
--- a/cmdline/cmdline.h
+++ b/cmdline/cmdline.h
@@ -234,7 +234,7 @@
     // Checks for --boot-image location.
     {
       std::string boot_image_location = boot_image_location_;
-      size_t file_name_idx = boot_image_location.rfind("/");
+      size_t file_name_idx = boot_image_location.rfind('/');
       if (file_name_idx == std::string::npos) {  // Prevent a InsertIsaDirectory check failure.
         *error_msg = "Boot image location must have a / in it";
         return false;
@@ -244,7 +244,7 @@
       // This prevents a common error "Could not create an image space..." when initing the Runtime.
       if (file_name_idx != std::string::npos) {
         std::string no_file_name = boot_image_location.substr(0, file_name_idx);
-        size_t ancestor_dirs_idx = no_file_name.rfind("/");
+        size_t ancestor_dirs_idx = no_file_name.rfind('/');
 
         std::string parent_dir_name;
         if (ancestor_dirs_idx != std::string::npos) {
diff --git a/cmdline/cmdline_parser.h b/cmdline/cmdline_parser.h
index cfc0967..d82fd48 100644
--- a/cmdline/cmdline_parser.h
+++ b/cmdline/cmdline_parser.h
@@ -390,7 +390,7 @@
         // Unlike regular argument definitions, when a value gets parsed into its
         // stronger type, we just throw it away.
 
-        if (ign.find("_") != std::string::npos) {  // Does the arg-def have a wildcard?
+        if (ign.find('_') != std::string::npos) {  // Does the arg-def have a wildcard?
           // pretend this is a string, e.g. -Xjitconfig:<anythinggoeshere>
           auto&& builder = Define(ignore_name).template WithType<std::string>().IntoIgnore();
           assert(&builder == this);
diff --git a/cmdline/cmdline_parser_test.cc b/cmdline/cmdline_parser_test.cc
index cad5104..550e8c4 100644
--- a/cmdline/cmdline_parser_test.cc
+++ b/cmdline/cmdline_parser_test.cc
@@ -78,7 +78,7 @@
     return memcmp(std::addressof(expected), std::addressof(actual), sizeof(expected)) == 0;
   }
 
-  bool UsuallyEquals(const char* expected, std::string actual) {
+  bool UsuallyEquals(const char* expected, const std::string& actual) {
     return std::string(expected) == actual;
   }
 
@@ -129,7 +129,7 @@
     parser_ = ParsedOptions::MakeParser(false);  // do not ignore unrecognized options
   }
 
-  static ::testing::AssertionResult IsResultSuccessful(CmdlineResult result) {
+  static ::testing::AssertionResult IsResultSuccessful(const CmdlineResult& result) {
     if (result.IsSuccess()) {
       return ::testing::AssertionSuccess();
     } else {
@@ -138,7 +138,7 @@
     }
   }
 
-  static ::testing::AssertionResult IsResultFailure(CmdlineResult result,
+  static ::testing::AssertionResult IsResultFailure(const CmdlineResult& result,
                                                     CmdlineResult::Status failure_status) {
     if (result.IsSuccess()) {
       return ::testing::AssertionFailure() << " got success but expected failure: "
diff --git a/cmdline/cmdline_types.h b/cmdline/cmdline_types.h
index a5bb117..3f55eef 100644
--- a/cmdline/cmdline_types.h
+++ b/cmdline/cmdline_types.h
@@ -696,7 +696,7 @@
   }
 
   static std::string RemovePrefix(const std::string& source) {
-    size_t prefix_idx = source.find(":");
+    size_t prefix_idx = source.find(':');
 
     if (prefix_idx == std::string::npos) {
       return "";
diff --git a/cmdline/detail/cmdline_parse_argument_detail.h b/cmdline/detail/cmdline_parse_argument_detail.h
index 84beff5..14eac30 100644
--- a/cmdline/detail/cmdline_parse_argument_detail.h
+++ b/cmdline/detail/cmdline_parse_argument_detail.h
@@ -108,7 +108,7 @@
       // If this is true, then the wildcard matching later on can still fail, so this is not
       // a guarantee that the argument is correct, it's more of a strong hint that the
       // user-provided input *probably* was trying to match this argument.
-      size_t MaybeMatches(TokenRange token_list) const {
+      size_t MaybeMatches(const TokenRange& token_list) const {
         auto best_match = FindClosestMatch(token_list);
 
         return best_match.second;
@@ -118,7 +118,7 @@
       //
       // Returns the token range that was the closest match and the # of tokens that
       // this range was matched up until.
-      std::pair<const TokenRange*, size_t> FindClosestMatch(TokenRange token_list) const {
+      std::pair<const TokenRange*, size_t> FindClosestMatch(const TokenRange& token_list) const {
         const TokenRange* best_match_ptr = nullptr;
 
         size_t best_match = 0;