DevTools: add CSS.FontsUpdated event to signify that WebFont has loaded.

third_party/WebKit/Source/core/dom/StyleEngine.cpp

 /*
  * 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, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 557 matching lines @@
 }
 
 void StyleEngine::fontsNeedUpdate(CSSFontSelector*)
 {
     if (!document().isActive())
         return;
 
     if (m_resolver)
         m_resolver->invalidateMatchedPropertiesCache();
     document().setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::Fonts));
+    InspectorInstrumentation::fontsUpdated(m_document);
 }
 
 void StyleEngine::setFontSelector(CSSFontSelector* fontSelector)
 {
     if (m_fontSelector)
         m_fontSelector->unregisterForInvalidationCallbacks(this);
     m_fontSelector = fontSelector;
     if (m_fontSelector)
         m_fontSelector->registerForInvalidationCallbacks(this);
 }
@@ skipping 240 matching lines @@
 
 DEFINE_TRACE_WRAPPERS(StyleEngine)
 {
     for (auto sheet : m_injectedAuthorStyleSheets) {
         visitor->traceWrappers(sheet);
     }
     visitor->traceWrappers(m_documentStyleSheetCollection);
 }
 
 } // namespace blink