Implement BroadcastChannel

third_party/WebKit/Source/wtf/HashTraits.h

Index: third_party/WebKit/Source/wtf/HashTraits.h
diff --git a/third_party/WebKit/Source/wtf/HashTraits.h b/third_party/WebKit/Source/wtf/HashTraits.h
index 113ebac0035d05d07b3cd842baa0a77d1c8dcb0c..77d4ff6bc35987f584449ad72aed5c9bfcd1347a 100644
--- a/third_party/WebKit/Source/wtf/HashTraits.h
+++ b/third_party/WebKit/Source/wtf/HashTraits.h
@@ -245,6 +245,9 @@ struct PairHashTraits : GenericHashTraits<std::pair<typename FirstTraitsArg::Tra
     static const bool emptyValueIsZero = FirstTraits::emptyValueIsZero && SecondTraits::emptyValueIsZero;
     static EmptyValueType emptyValue() { return std::make_pair(FirstTraits::emptyValue(), SecondTraits::emptyValue()); }
 
+    static const bool hasIsEmptyValueFunction = FirstTraits::hasIsEmptyValueFunction || SecondTraits::hasIsEmptyValueFunction;

[haraken, 2016/06/02 04:23:41]

Would you elaborate why you need this change? Is this an existing bug of
WTF::HashMap?

[Marijn Kruisselbrink, 2016/06/02 18:33:30]

Yes, I'd say this is an existing bug of the std::pair HashTraits. It was
possible to have a HashMap<RefPtr<SecurityOrigin>, T>, and it was possible to
have a HashMap<std::pair<T, U>, V>, but the last one only if both T and U don't
use a custom isEmptyValue function. With this change it becomes possible to use
types with isEmptyValue functions inside std::pair in HashMap and friends as
well.

[haraken, 2016/06/03 05:33:03]

Would you make the change in a separate CL?

[Marijn Kruisselbrink, 2016/06/03 20:37:04]

Split off into https://codereview.chromium.org/2042453002

+    static bool isEmptyValue(const TraitType& value) { return isHashTraitsEmptyValue<FirstTraits>(value.first) && isHashTraitsEmptyValue<SecondTraits>(value.second); }
+
     static const unsigned minimumTableSize = FirstTraits::minimumTableSize;
 
     static void constructDeletedValue(TraitType& slot, bool zeroValue)