Let the canonical name of invalid encoding be an empty string

base/i18n/character_encoding.cc

Index: base/i18n/character_encoding.cc
diff --git a/base/i18n/character_encoding.cc b/base/i18n/character_encoding.cc
index fd0553a148eb707b25235015241640bfaa5b9440..05d2f50fff216b66cdf805a1c92ade49c9642e74 100644
--- a/base/i18n/character_encoding.cc
+++ b/base/i18n/character_encoding.cc
@@ -24,10 +24,10 @@ const char* const kCanonicalEncodingNames[] = {
 
 }  // namespace
 
-const char* GetCanonicalEncodingNameByAliasName(const std::string& alias_name) {
+std::string GetCanonicalEncodingNameByAliasName(const std::string& alias_name) {
   for (auto& encoding_name : kCanonicalEncodingNames) {
     if (alias_name == encoding_name)
-      return encoding_name;
+      return alias_name;
   }
   static const char* kStandards[3] = {"HTML", "MIME", "IANA"};
   for (auto& standard : kStandards) {
@@ -37,6 +37,6 @@ const char* GetCanonicalEncodingNameByAliasName(const std::string& alias_name) {
     if (U_SUCCESS(error_code) && canonical_name)
       return canonical_name;
   }
-  return nullptr;
+  return std::string();
 }
 }  // namespace base