Catch uncaught promise rejections from V8 and log to console.

Source/bindings/core/v8/ScriptValue.cpp

Index: Source/bindings/core/v8/ScriptValue.cpp
diff --git a/Source/bindings/core/v8/ScriptValue.cpp b/Source/bindings/core/v8/ScriptValue.cpp
index 5b7a362ce41c97e9952fceecdb756f13e0f14e18..c7e9918b131c19ec56172f1d8176aab366ea5768 100644
--- a/Source/bindings/core/v8/ScriptValue.cpp
+++ b/Source/bindings/core/v8/ScriptValue.cpp
@@ -37,6 +37,17 @@
 
 namespace blink {
 
+int ScriptValue::identityHash() const
+{
+    if (isEmpty())
+        return 0;
+    v8::HandleScope handleScope(isolate());
+    v8::Local<v8::Value> value = m_value->newLocal(isolate());
+    if (!value->IsObject())
+        return 0;
+    return v8::Local<v8::Object>::Cast(value)->GetIdentityHash();
+}
+
 v8::Handle<v8::Value> ScriptValue::v8Value() const
 {
     if (isEmpty())