Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/Source/core/loader/FrameFetchContext.cpp

Index: third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
index c03a3c391e4a9f1bea679846a5bf6dc102db9466..0957d5f68a2ad88cdd258b747588370d04c5aa8b 100644
--- a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
@@ -79,6 +79,7 @@
 #include "platform/network/NetworkUtils.h"
 #include "platform/weborigin/SchemeRegistry.h"
 #include "platform/wtf/Vector.h"
+#include "public/platform/Platform.h"
 #include "public/platform/WebCachePolicy.h"
 #include "public/platform/WebInsecureRequestPolicy.h"
 #include "public/platform/WebViewScheduler.h"
@@ -1081,6 +1082,10 @@ RefPtr<WebTaskRunner> FrameFetchContext::LoadingTaskRunner() const {
   return GetFrame()->FrameScheduler()->LoadingTaskRunner();
 }
 
+std::unique_ptr<WebURLLoader> FrameFetchContext::CreateURLLoader() {
+  return Platform::Current()->CreateURLLoader();
+}
+
 DEFINE_TRACE(FrameFetchContext) {
   visitor->Trace(document_loader_);
   BaseFetchContext::Trace(visitor);