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

Source/platform/fonts/shaping/HarfBuzzShaper.cpp

Index: Source/platform/fonts/shaping/HarfBuzzShaper.cpp
diff --git a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
index 90d7f243a8486c0e13432444a9031393d30c86c7..ed89ad65ee5a185d67df80dfd42dc93237a0fa4f 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
+++ b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
@@ -839,7 +839,8 @@ bool HarfBuzzShaper::shapeHarfBuzzRuns()
 
         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);