Add 'XHR' to the Resource::Type enum, and use it for XHR requests.

Source/core/fetch/Resource.cpp

Index: Source/core/fetch/Resource.cpp
diff --git a/Source/core/fetch/Resource.cpp b/Source/core/fetch/Resource.cpp
index 36d47f13b00e5b33b943f55d748c1403a64c8919..069e2a948a92e93a0fbe7ca7d8a1306ea3314cc5 100644
--- a/Source/core/fetch/Resource.cpp
+++ b/Source/core/fetch/Resource.cpp
@@ -528,7 +528,7 @@ void Resource::allClientsRemoved()
 {
     if (!m_loader)
         return;
-    if (m_type == MainResource || m_type == Raw)
+    if (m_type == MainResource || m_type == Raw || m_type == XMLHttpRequest)
         cancelTimerFired(&m_cancelTimer);
     else if (!m_cancelTimer.isActive())
         m_cancelTimer.startOneShot(0, FROM_HERE);
@@ -955,6 +955,8 @@ const char* Resource::resourceTypeToString(Type type, const FetchInitiatorInfo&
         return "Imported resource";
     case Resource::Media:
         return "Media";
+    case Resource::XMLHttpRequest:
+        return "XMLHttpRequest";
     }
     ASSERT_NOT_REACHED();
     return initatorTypeNameToString(initiatorInfo.name);
@@ -990,6 +992,8 @@ const char* ResourceTypeName(Resource::Type type)
         return "ImportResource";
     case Resource::Media:
         return "Media";
+    case Resource::XMLHttpRequest:
+        return "XMLHttpRequest";
     }
     ASSERT_NOT_REACHED();
     return "Unknown";