Color parsing in CSSParser: avoid using ColorValueCache on worker thread

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

 /*
  * Copyright (C) 2011, 2012 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/css/CSSValuePool.h"
 
 #include "core/css/CSSValueList.h"
 #include "core/css/parser/CSSParser.h"
 #include "core/style/ComputedStyle.h"
+#include "wtf/Threading.h"
 
 namespace blink {
 
 CSSValuePool& cssValuePool()
 {
     DEFINE_STATIC_LOCAL(OwnPtrWillBePersistent<CSSValuePool>, pool, (adoptPtrWillBeNoop(new CSSValuePool())));
     return *pool;
 }
 
 CSSValuePool::CSSValuePool()
@@ skipping 30 matching lines @@
 {
     // These are the empty and deleted values of the hash table.
     if (rgbValue == Color::transparent)
         return m_colorTransparent;
     if (rgbValue == Color::white)
         return m_colorWhite;
     // Just because it is common.
     if (rgbValue == Color::black)
         return m_colorBlack;
 
+    if (!isMainThread()) {
+        // TODO (crbug.com/599659): Make CSS color parsing work properly in a
+        // worker thread.
+        // Currently, ColorValueCache is not thread-safe; so we avoid interacting
+        // with it on a non-main thread.
+        return CSSColorValue::create(rgbValue);
+    }
+
     // Just wipe out the cache and start rebuilding if it gets too big.
     const unsigned maximumColorCacheSize = 512;
     if (m_colorValueCache.size() > maximumColorCacheSize)
         m_colorValueCache.clear();
 
     RefPtrWillBeRawPtr<CSSColorValue> dummyValue = nullptr;
     ColorValueCache::AddResult entry = m_colorValueCache.add(rgbValue, dummyValue);
     if (entry.isNewEntry)
         entry.storedValue->value = CSSColorValue::create(rgbValue);
+
     return entry.storedValue->value;
 }
 
 PassRefPtrWillBeRawPtr<CSSPrimitiveValue> CSSValuePool::createValue(double value, CSSPrimitiveValue::UnitType type)
 {
     if (std::isinf(value))
         value = 0;
 
     if (value < 0 || value > maximumCacheableIntegerValue)
         return CSSPrimitiveValue::create(value, type);
@@ skipping 66 matching lines @@
     visitor->trace(m_colorBlack);
     visitor->trace(m_pixelValueCache);
     visitor->trace(m_percentValueCache);
     visitor->trace(m_numberValueCache);
     visitor->trace(m_fontFaceValueCache);
     visitor->trace(m_fontFamilyValueCache);
 #endif
 }
 
 } // namespace blink