Apply all blink changes between @202695 and tip of trunk

Source/bindings/core/dart/DartJsInteropData.cpp

Index: Source/bindings/core/dart/DartJsInteropData.cpp
diff --git a/Source/bindings/core/dart/DartJsInteropData.cpp b/Source/bindings/core/dart/DartJsInteropData.cpp
index ddad8454cfe4cbfd15fe5a12e62484bead3e6e8b..00776e6aad51f6771bf11e79dcd2b07fb99b8c3a 100644
--- a/Source/bindings/core/dart/DartJsInteropData.cpp
+++ b/Source/bindings/core/dart/DartJsInteropData.cpp
@@ -30,7 +30,9 @@
 #include "config.h"
 
 #include "bindings/core/dart/DartJsInteropData.h"
+#include "bindings/core/dart/V8Converter.h"
 
+#include <dart_api.h>
 #include <string.h>
 
 namespace blink {
@@ -73,4 +75,13 @@ v8::Local<v8::Function> DartJsInteropData::instanceofFunction()
     return cacheFunction(&m_instanceofFunction, "(function (type) { return this instanceof type; })");
 }
 
+v8::Local<v8::String> DartJsInteropData::existingDartWrapperHiddenField(v8::Isolate* v8Isolate) {
+    if (m_existingDartWrapperHiddenField.IsEmpty()) {
+        // We are abusing Dart_DebugName() as it is supposed to give a unique
+        // per isolate name.
+        m_existingDartWrapperHiddenField.Reset(v8Isolate, v8::String::Concat(v8::String::NewFromUtf8(v8Isolate, "$existing_dart_wrapper_"), V8Converter::stringToV8(Dart_DebugName())));
+    }
+    return v8::Local<v8::String>::New(v8Isolate, m_existingDartWrapperHiddenField);
+}
+
 }