Add an Error class for ServiceWorkers

Source/modules/serviceworkers/ServiceWorkerError.cpp

Index: Source/modules/serviceworkers/ServiceWorkerError.cpp
diff --git a/Source/core/html/HTMLMediaSource.cpp b/Source/modules/serviceworkers/ServiceWorkerError.cpp
similarity index 83%
copy from Source/core/html/HTMLMediaSource.cpp
copy to Source/modules/serviceworkers/ServiceWorkerError.cpp
index 7221cfeaf34ed4e40fd174029a3fa66a6d8dd411..8d132cd6982e26e8a174de77885cbad2e2d2ad55 100644
--- a/Source/core/html/HTMLMediaSource.cpp
+++ b/Source/modules/serviceworkers/ServiceWorkerError.cpp
@@ -29,16 +29,19 @@
  */
 
 #include "config.h"
-#include "core/html/HTMLMediaSource.h"
+#include "ServiceWorkerError.h"
 
+using WebKit::WebServiceWorkerError;
 namespace WebCore {
 
-URLRegistry* HTMLMediaSource::s_registry = 0;
-
-void HTMLMediaSource::setRegistry(URLRegistry* registry)
+String ServiceWorkerError::GetErrorString(WebKit::WebServiceWorkerError::ErrorType type)
 {
-    ASSERT(!s_registry);
-    s_registry = registry;
+    switch (type) {
+    case WebServiceWorkerError::RegistrationError:
+        return "RegistrationError";
+    default:
+        ASSERT_NOT_REACHED();
+    }
 }
 
 }