AK: Add StringView(ReadonlyBytes) constructor.

Author: https://github.com/asynts
Commit: ebce4ead40
Pull-request: https://github.com/SerenityOS/serenity/pull/3220
Reviewed-by: https://github.com/awesomekling

AK/StringView.h

@@ -57,6 +57,11 @@ public:
         , m_length(cstring ? __builtin_strlen(cstring) : 0)
     {
     }
+    ALWAYS_INLINE StringView(ReadonlyBytes bytes)
+        : m_characters(reinterpret_cast<const char*>(bytes.data()))
+        , m_length(bytes.size())
+    {
+    }
 
     StringView(const ByteBuffer&);
     StringView(const String&);