Add methods for creating V8 extras-based ReadableStreams from C++

Source/core/testing/v8/WebCoreTestSupport.cpp

 /*
  * Copyright (C) 2011 Google 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
@@ skipping 26 matching lines @@
 
 namespace WebCoreTestSupport {
 
 void injectInternalsObject(v8::Local<v8::Context> context)
 {
     ScriptState* scriptState = ScriptState::from(context);
     ScriptState::Scope scope(scriptState);
     v8::Local<v8::Object> global = scriptState->context()->Global();
     ExecutionContext* executionContext = scriptState->executionContext();
     if (executionContext->isDocument()) {
-        v8::Local<v8::Value> internals = toV8(Internals::create(toDocument(executionContext)), global, scriptState->isolate());
+        v8::Local<v8::Value> internals = toV8(Internals::create(scriptState), global, scriptState->isolate());
         ASSERT(!internals.IsEmpty());
         v8CallOrCrash(global->Set(scriptState->context(), v8AtomicString(scriptState->isolate(), Internals::internalsId), internals));
     }
 }
 
 void resetInternalsObject(v8::Local<v8::Context> context)
 {
     // This can happen if JavaScript is disabled in the main frame.
     if (context.IsEmpty())
         return;
 
     ScriptState* scriptState = ScriptState::from(context);
     ScriptState::Scope scope(scriptState);
     Page* page = toDocument(scriptState->executionContext())->frame()->page();
     ASSERT(page);
     Internals::resetToConsistentState(page);
     InternalSettings::from(*page)->resetToConsistentState();
 }
 
 }