Clear matched properties cache for theme color changes.

Source/core/dom/StyleEngine.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 152 matching lines @@
     unsigned resolverAccessCount() const;
 
     void markDocumentDirty();
 
     PassRefPtrWillBeRawPtr<CSSStyleSheet> createSheet(Element*, const String& text, TextPosition startPosition, bool createdByParser);
     void removeSheet(StyleSheetContents*);
 
     bool onlyDocumentHasStyles() const { return m_activeTreeScopes.isEmpty(); }
     void collectScopedStyleFeaturesTo(RuleFeatureSet&) const;
 
+    void platformColorsChanged();
+
     virtual void trace(Visitor*) override;
 
 private:
     // CSSFontSelectorClient implementation.
     virtual void fontsNeedUpdate(CSSFontSelector*) override;
 
 private:
     StyleEngine(Document&);
 
     TreeScopeStyleSheetCollection* ensureStyleSheetCollectionFor(TreeScope&);
@@ skipping 63 matching lines @@
 
     RefPtrWillBeMember<CSSFontSelector> m_fontSelector;
 
     WillBeHeapHashMap<AtomicString, RawPtrWillBeMember<StyleSheetContents> > m_textToSheetCache;
     WillBeHeapHashMap<RawPtrWillBeMember<StyleSheetContents>, AtomicString> m_sheetToTextCache;
 };
 
 }
 
 #endif