Introduce ThreadableLoadingContext: make threaded loading code one step away from Document

third_party/WebKit/Source/web/WebAssociatedURLLoaderImpl.cpp

Index: third_party/WebKit/Source/web/WebAssociatedURLLoaderImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebAssociatedURLLoaderImpl.cpp b/third_party/WebKit/Source/web/WebAssociatedURLLoaderImpl.cpp
index fdc51d5179bb8671294b4fb2a6d363c5f5b9013d..7c7e5adc515be1058dc68e0305b749d078bb5e37 100644
--- a/third_party/WebKit/Source/web/WebAssociatedURLLoaderImpl.cpp
+++ b/third_party/WebKit/Source/web/WebAssociatedURLLoaderImpl.cpp
@@ -30,10 +30,13 @@
 
 #include "web/WebAssociatedURLLoaderImpl.h"
 
+#include <limits.h>
+#include <memory>
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/loader/DocumentThreadableLoader.h"
 #include "core/loader/DocumentThreadableLoaderClient.h"
+#include "core/loader/ThreadableLoadingContext.h"
 #include "platform/Timer.h"
 #include "platform/exported/WrappedResourceRequest.h"
 #include "platform/exported/WrappedResourceResponse.h"
@@ -51,8 +54,6 @@
 #include "wtf/HashSet.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/text/WTFString.h"
-#include <limits.h>
-#include <memory>
 
 namespace blink {
 
@@ -421,7 +422,8 @@ void WebAssociatedURLLoaderImpl::loadAsynchronously(
     Document* document = toDocument(m_observer->lifecycleContext());
     DCHECK(document);
     m_loader = DocumentThreadableLoader::create(
-        *document, m_clientAdapter.get(), options, resourceLoaderOptions);
+        *ThreadableLoadingContext::create(*document), m_clientAdapter.get(),
+        options, resourceLoaderOptions);
     m_loader->start(webcoreRequest);
   }