WTF: Add comments and tests for Unicode aware case-insensitive string operations.

third_party/WebKit/Source/wtf/text/StringView.h

Index: third_party/WebKit/Source/wtf/text/StringView.h
diff --git a/third_party/WebKit/Source/wtf/text/StringView.h b/third_party/WebKit/Source/wtf/text/StringView.h
index 9059e88d869c765c31d6b4d271a3a444879d645c..17680d9a28fa1c3176cee9da4fbc79fdd5018844 100644
--- a/third_party/WebKit/Source/wtf/text/StringView.h
+++ b/third_party/WebKit/Source/wtf/text/StringView.h
@@ -215,12 +215,15 @@ inline void StringView::set(const StringImpl& impl,
     m_characters16 = impl.characters16() + offset;
 }
 
+// Unicode aware case insensitive string matching. Non-ASCII characters might
+// match to ASCII characters. These functions are rarely used to implement web
+// platform features.
 WTF_EXPORT bool equalIgnoringCase(const StringView&, const StringView&);
-WTF_EXPORT bool equalIgnoringASCIICase(const StringView&, const StringView&);
-
 WTF_EXPORT bool equalIgnoringCaseAndNullity(const StringView&,
                                             const StringView&);
 
+WTF_EXPORT bool equalIgnoringASCIICase(const StringView&, const StringView&);
+
 // TODO(esprehn): Can't make this an overload of WTF::equal since that makes
 // calls to equal() that pass literal strings ambiguous. Figure out if we can
 // replace all the callers with equalStringView and then rename it to equal().