Add ResourceType::PING. and mark those requests as detachable.

webkit/common/resource_type.h

Index: webkit/common/resource_type.h
diff --git a/webkit/common/resource_type.h b/webkit/common/resource_type.h
index 9ec79097717ca618de12a055d7e6d4f7705e4af0..0aec50a4a80d0ce59984ef3225cb9e20bb6bd948 100644
--- a/webkit/common/resource_type.h
+++ b/webkit/common/resource_type.h
@@ -29,6 +29,7 @@ class ResourceType {
     PREFETCH,        // an explicitly requested prefetch
     FAVICON,         // a favicon
     XHR,             // a XMLHttpRequest
+    PING,            // a ping request for <a ping>
     LAST_TYPE        // Place holder so we don't need to change ValidType
                      // everytime.
   };