Make FontFaceCache::version return unique number across all instances

third_party/WebKit/Source/core/css/FontFaceCache.cpp

 /*
  * Copyright (C) 2007, 2008, 2011 Apple Inc. All rights reserved.
  * 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 22 matching lines @@
 #include "core/css/FontStyleMatcher.h"
 #include "core/css/StyleRule.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/loader/resource/FontResource.h"
 #include "platform/FontFamilyNames.h"
 #include "platform/fonts/FontDescription.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
+static unsigned s_version = 0;
+
 FontFaceCache::FontFaceCache() : m_version(0) {}
 
 void FontFaceCache::add(CSSFontSelector* cssFontSelector,
                         const StyleRuleFontFace* fontFaceRule,
                         FontFace* fontFace) {
   if (!m_styleRuleToFontFace.add(fontFaceRule, fontFace).isNewEntry)
     return;
   addFontFace(cssFontSelector, fontFace, true);
 }
 
@@ skipping 11 matching lines @@
   if (!segmentedFontFaceResult.storedValue->value)
     segmentedFontFaceResult.storedValue->value =
         CSSSegmentedFontFace::create(cssFontSelector, fontFace->traits());
 
   segmentedFontFaceResult.storedValue->value->addFontFace(fontFace,
                                                           cssConnected);
   if (cssConnected)
     m_cssConnectedFontFaces.add(fontFace);
 
   m_fonts.remove(fontFace->family());
-  ++m_version;
+  incrementVersion();
 }
 
 void FontFaceCache::remove(const StyleRuleFontFace* fontFaceRule) {
   StyleRuleToFontFace::iterator it = m_styleRuleToFontFace.find(fontFaceRule);
   if (it != m_styleRuleToFontFace.end()) {
     removeFontFace(it->value.get(), true);
     m_styleRuleToFontFace.remove(it);
   }
 }
 
@@ skipping 13 matching lines @@
   segmentedFontFace->removeFontFace(fontFace);
   if (segmentedFontFace->isEmpty()) {
     familyFontFaces->remove(familyFontFacesIter);
     if (familyFontFaces->isEmpty())
       m_fontFaces.remove(fontFacesIter);
   }
   m_fonts.remove(fontFace->family());
   if (cssConnected)
     m_cssConnectedFontFaces.remove(fontFace);
 
-  ++m_version;
+  incrementVersion();
 }
 
 void FontFaceCache::clearCSSConnected() {
   for (const auto& item : m_styleRuleToFontFace)
     removeFontFace(item.value.get(), true);
   m_styleRuleToFontFace.clear();
 }
 
 void FontFaceCache::clearAll() {
   if (m_fontFaces.isEmpty())
     return;
 
   m_fontFaces.clear();
   m_fonts.clear();
   m_styleRuleToFontFace.clear();
   m_cssConnectedFontFaces.clear();
-  ++m_version;
+  incrementVersion();
+}
+
+void FontFaceCache::incrementVersion() {
+  m_version = ++s_version;

[drott, 2017/01/24 12:16:20]

I assume multiple documents in the same renderer would all still be on the main
thread? We don't need anything like an atomic increment here?

 }
 
 CSSSegmentedFontFace* FontFaceCache::get(const FontDescription& fontDescription,
                                          const AtomicString& family) {
   TraitsMap* familyFontFaces = m_fontFaces.get(family);
   if (!familyFontFaces || familyFontFaces->isEmpty())
     return nullptr;
 
   FamilyToTraitsMap::AddResult traitsResult = m_fonts.add(family, nullptr);
   if (!traitsResult.storedValue->value)
@@ skipping 16 matching lines @@
 }
 
 DEFINE_TRACE(FontFaceCache) {
   visitor->trace(m_fontFaces);
   visitor->trace(m_fonts);
   visitor->trace(m_styleRuleToFontFace);
   visitor->trace(m_cssConnectedFontFaces);
 }
 
 }  // namespace blink