Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp

Index: third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp b/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
index 15c1f33920f1d6ea47ae5009b9877e0679c52c79..5b8030ab99b853facaa83123afdaa7120b319090 100644
--- a/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
@@ -40,6 +40,7 @@
 #include "core/inspector/ConsoleMessage.h"
 #include "core/inspector/ConsoleMessageStorage.h"
 #include "core/inspector/WorkerThreadDebugger.h"
+#include "core/loader/WorkerFetchContext.h"
 #include "core/loader/WorkerThreadableLoader.h"
 #include "core/probe/CoreProbes.h"
 #include "core/workers/WorkerClients.h"
@@ -51,6 +52,7 @@
 #include "core/workers/WorkerThread.h"
 #include "platform/CrossThreadFunctional.h"
 #include "platform/InstanceCounters.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/loader/fetch/MemoryCache.h"
 #include "platform/network/ContentSecurityPolicyParsers.h"
 #include "platform/weborigin/KURL.h"
@@ -300,6 +302,14 @@ ExecutionContext* WorkerGlobalScope::GetExecutionContext() const {
   return const_cast<WorkerGlobalScope*>(this);
 }
 
+WorkerFetchContext* WorkerGlobalScope::FetchContext() {
+  DCHECK(RuntimeEnabledFeatures::offMainThreadFetchEnabled());
+  if (fetch_context_)
+    return fetch_context_;
+  fetch_context_ = WorkerFetchContext::Create(*this);
+  return fetch_context_;
+}
+
 WorkerGlobalScope::WorkerGlobalScope(
     const KURL& url,
     const String& user_agent,
@@ -376,6 +386,7 @@ DEFINE_TRACE(WorkerGlobalScope) {
   visitor->Trace(timers_);
   visitor->Trace(event_listeners_);
   visitor->Trace(pending_error_events_);
+  visitor->Trace(fetch_context_);
   ExecutionContext::Trace(visitor);
   EventTargetWithInlineData::Trace(visitor);
   SecurityContext::Trace(visitor);