Add an Error class for ServiceWorkers

public/platform/WebServiceWorkerError.h

Index: public/platform/WebServiceWorkerError.h
diff --git a/public/platform/WebGraphicsContext3DProvider.h b/public/platform/WebServiceWorkerError.h
similarity index 82%
copy from public/platform/WebGraphicsContext3DProvider.h
copy to public/platform/WebServiceWorkerError.h
index dba2216773526377c53b27a9d6830bce0c25fc48..18be2c93f8f504954f705c604890311aed5a9e99 100644
--- a/public/platform/WebGraphicsContext3DProvider.h
+++ b/public/platform/WebServiceWorkerError.h
@@ -28,22 +28,23 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef WebGraphicsContext3DProvider_h
-#define WebGraphicsContext3DProvider_h
+#ifndef WebServiceWorkerError_h
+#define WebServiceWorkerError_h
 
-#include "WebCommon.h"
-
-class GrContext;
+#include "WebString.h"
 
 namespace WebKit {
-class WebGraphicsContext3D;
 
-class WebGraphicsContext3DProvider {
-public:
-    virtual ~WebGraphicsContext3DProvider() { }
+struct WebServiceWorkerError {
+    enum ErrorType {
+        DisabledError = 0
+    };
+
+    WebServiceWorkerError(ErrorType errorType, const WebString& message)
+        : errorType(errorType), message(message) { }
 
-    virtual WebGraphicsContext3D* context3d() = 0;
-    virtual GrContext* grContext() = 0;
+    ErrorType errorType;
+    WebString message;
 };
 
 } // namespace WebKit