[DO NOT COMMIT] Trace events for layout-based First Meaningful Paint detection

third_party/WebKit/Source/core/css/FontFace.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 515 matching lines @@
                 break;
             default:
                 break;
             }
         }
     }
 
     return FontTraits(style, variant, weight, stretch);
 }
 
+bool FontFace::isBlank() const
+{
+    return m_status == Loading && m_charCount > 200 && m_cssFontFace->isBlank();
+}
+
 static FontDisplay CSSValueToFontDisplay(CSSValue* value)
 {
     if (value && value->isPrimitiveValue()) {
         switch (toCSSPrimitiveValue(value)->getValueID()) {
         case CSSValueAuto:
             return FontDisplayAuto;
         case CSSValueBlock:
             return FontDisplayBlock;
         case CSSValueSwap:
             return FontDisplaySwap;
@@ skipping 71 matching lines @@
 
     RefPtr<SharedBuffer> buffer = SharedBuffer::create(data, size);
     BinaryDataFontFaceSource* source = new BinaryDataFontFaceSource(buffer.get(), m_otsParseMessage);
     if (source->isValid())
         setLoadStatus(Loaded);
     else
         setError(DOMException::create(SyntaxError, "Invalid font data in ArrayBuffer."));
     m_cssFontFace->addSource(source);
 }
 
+bool FontFace::willUseFontData(const FontDescription& fontDescription, const String& text)
+{
+    if (m_status != Loaded) {
+        m_charCount += text.length();
+        // if (m_cssFontFace->isBlank())
+        //     fprintf(stderr, "%s %u %u\n", m_family.getString().ascii().data(), length, m_charCount);
+    }
+    if (loadStatus() != Unloaded)
+        return true;
+    if (cssFontFace()->maybeScheduleFontLoad(fontDescription, text.characterStartingAt(0))) {
+        return true;
+    }
+    return false;
+}
+
 DEFINE_TRACE(FontFace)
 {
     visitor->trace(m_style);
     visitor->trace(m_weight);
     visitor->trace(m_stretch);
     visitor->trace(m_unicodeRange);
     visitor->trace(m_variant);
     visitor->trace(m_featureSettings);
     visitor->trace(m_display);
     visitor->trace(m_error);
     visitor->trace(m_loadedProperty);
     visitor->trace(m_cssFontFace);
     visitor->trace(m_callbacks);
     ActiveDOMObject::trace(visitor);
 }
 
 bool FontFace::hadBlankText() const
 {
     return m_cssFontFace->hadBlankText();
 }
 
 bool FontFace::hasPendingActivity() const
 {
     return m_status == Loading && getExecutionContext() && !getExecutionContext()->activeDOMObjectsAreStopped();
 }
 
 } // namespace blink