[ServiceWorker] Support setting body to Request object in ServiceWorker.

Source/modules/serviceworkers/FetchRequestData.h

Index: Source/modules/serviceworkers/FetchRequestData.h
diff --git a/Source/modules/serviceworkers/FetchRequestData.h b/Source/modules/serviceworkers/FetchRequestData.h
index 943e6a52b6e8a2baf93bb7583d8c5a170585b984..574d655dc9cc3eac415d797c81322a2c6306345f 100644
--- a/Source/modules/serviceworkers/FetchRequestData.h
+++ b/Source/modules/serviceworkers/FetchRequestData.h
@@ -83,6 +83,7 @@ public:
     Tainting tainting() const { return m_responseTainting; }
     FetchHeaderList* headerList() { return m_headerList.get(); }
     PassRefPtr<BlobDataHandle> blobDataHandle() const { return m_blobDataHandle; }
+    void setBlobDataHandle(PassRefPtr<BlobDataHandle> blobHandle) { m_blobDataHandle = blobHandle; }
 
     void trace(Visitor*);