bindings: Add C++ versions of WebIDL types and generalize NativeValueTraits.

third_party/WebKit/Source/bindings/tests/results/core/UnrestrictedDoubleOrString.cpp

Index: third_party/WebKit/Source/bindings/tests/results/core/UnrestrictedDoubleOrString.cpp
diff --git a/third_party/WebKit/Source/bindings/tests/results/core/UnrestrictedDoubleOrString.cpp b/third_party/WebKit/Source/bindings/tests/results/core/UnrestrictedDoubleOrString.cpp
index 74e8e355b007881743f56e5f067c9bdfdc90ffc1..7bd592f85a60d7bbb35d3e4a7d5e135873098da5 100644
--- a/third_party/WebKit/Source/bindings/tests/results/core/UnrestrictedDoubleOrString.cpp
+++ b/third_party/WebKit/Source/bindings/tests/results/core/UnrestrictedDoubleOrString.cpp
@@ -11,7 +11,9 @@
 // clang-format off
 #include "UnrestrictedDoubleOrString.h"
 
+#include "bindings/core/v8/IDLTypes.h"
 #include "bindings/core/v8/ToV8.h"
+#include "bindings/core/v8/V8BindingForIDLTypes.h"
 
 namespace blink {
 
@@ -66,7 +68,7 @@ void V8UnrestrictedDoubleOrString::toImpl(v8::Isolate* isolate, v8::Local<v8::Va
     return;
 
   if (v8Value->IsNumber()) {
-    double cppValue = toDouble(isolate, v8Value, exceptionState);
+    double cppValue = NativeValueTraits<IDLUnrestrictedDouble>::nativeValue(isolate, v8Value, exceptionState);
     if (exceptionState.hadException())
       return;
     impl.setUnrestrictedDouble(cppValue);