Don't return false for RenderStyle::operator== while fonts load.

Source/platform/fonts/shaping/HarfBuzzShaper.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 BlackBerry Limited. 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.
@@ skipping 821 matching lines @@
 
         hb_buffer_set_language(harfBuzzBuffer.get(), hb_language_from_string(locale.data(), locale.length()));
         hb_buffer_set_script(harfBuzzBuffer.get(), currentRun->script());
         hb_buffer_set_direction(harfBuzzBuffer.get(), currentRun->direction());
 
         const UChar* src = m_normalizedBuffer.get() + currentRun->startIndex();
         std::wstring key(src, src + currentRun->numCharacters());
 
         CachedShapingResults* cachedResults = runCache.find(key);
         if (cachedResults) {
-            if (cachedResults->dir == currentRun->direction() && cachedResults->font == *m_font && cachedResults->locale == localeString) {
+            if (cachedResults->dir == currentRun->direction() && cachedResults->font == *m_font
+                && !cachedResults->font.loadingCustomFonts() && !m_font->loadingCustomFonts() && cachedResults->locale == localeString) {
                 currentRun->applyShapeResult(cachedResults->buffer);
                 setGlyphPositionsForHarfBuzzRun(currentRun, cachedResults->buffer);
 
                 hb_buffer_clear_contents(harfBuzzBuffer.get());
 
                 runCache.moveToBack(cachedResults);
 
                 continue;
             }
 
@@ skipping 289 matching lines @@
         fromX = 0;
     if (!foundToX)
         toX = m_run.rtl() ? 0 : m_totalWidth;
 
     if (fromX < toX)
         return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
     return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
 }
 
 } // namespace blink