Add setPriority to WebURLRequest

Source/platform/exported/WebURLRequest.cpp

Index: Source/platform/exported/WebURLRequest.cpp
diff --git a/Source/platform/exported/WebURLRequest.cpp b/Source/platform/exported/WebURLRequest.cpp
index a8e39f255c0981b0380e91f049b25e79a5524397..f74541315816c78cb0be49ab80c035cb613f5eae 100644
--- a/Source/platform/exported/WebURLRequest.cpp
+++ b/Source/platform/exported/WebURLRequest.cpp
@@ -321,6 +321,12 @@ WebURLRequest::Priority WebURLRequest::priority() const
         m_private->m_resourceRequest->priority());
 }
 
+void WebURLRequest::setPriority(WebURLRequest::Priority priority)
+{
+    m_private->m_resourceRequest->setPriority(
+        static_cast<ResourceLoadPriority>(priority));
+}
+
 const ResourceRequest& WebURLRequest::toResourceRequest() const
 {
     ASSERT(m_private);