Don't pass invalid Unicode codepoint to Skia

Bug: 15849380
Change-Id: Ib5285e57c5806bd399600fadd56e8bc809da323f

libs/minikin/Layout.cpp

@@ -258,6 +258,12 @@ static hb_bool_t harfbuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoin
     MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
     MinikinFont* font = paint->font;
     uint32_t glyph_id;
+    /* HarfBuzz replaces broken input codepoints with (unsigned int) -1.
+     * Skia expects valid Unicode.
+     * Replace invalid codepoints with U+FFFD REPLACEMENT CHARACTER.
+     */
+    if (unicode > 0x10FFFF)
+        unicode = 0xFFFD;
     bool ok = font->GetGlyph(unicode, &glyph_id);
     if (ok) {
         *glyph = glyph_id;