Clear baseLayoutStyle when the font selector version has increased.

Source/core/animation/ElementAnimations.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 99 matching lines @@
         ASSERT(*m_baseLayoutStyle == *layoutStyle);
 #endif
     m_baseLayoutStyle = LayoutStyle::clone(*layoutStyle);
 }
 
 void ElementAnimations::clearBaseLayoutStyle()
 {
     m_baseLayoutStyle = nullptr;
 }
 
+bool ElementAnimations::isAnimationStyleChange() const
+{
+    // TODO(rune@opera.com): The FontFaceCache version number may be increased without forcing
+    // a style recalc (see crbug.com/471079). LayoutStyle objects created with different cache
+    // versions will not be considered equal as Font::operator== will compare versions, hence
+    // LayoutStyle::operator== will return false. We avoid using baseLayoutStyle (the check for
+    // isFallbackValid()) in that case to avoid triggering the LayoutStyle comparison ASSERT
+    // in updateBaseLayoutStyle.
+    return m_animationStyleChange && (!m_baseLayoutStyle || m_baseLayoutStyle->font().isFallbackValid());
+}
+
 } // namespace blink