Add an Error class for ServiceWorkers

public/platform/WebServiceWorkerError.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef WebMIDIAccessor_h
-#define WebMIDIAccessor_h
+#ifndef WebServiceWorkerError_h
+#define WebServiceWorkerError_h
 
 #include "WebString.h"
 
 namespace WebKit {
 
-class WebMIDIAccessor {
-public:
-    virtual ~WebMIDIAccessor() { }
+struct WebServiceWorkerError {
+    enum ErrorType {
+        DisabledError = 0,
+        SecurityError
+    };
 
-    virtual void startSession() { }
-    // |timeStamp| is measured in milliseconds as Web MIDI spec defines.
-    virtual void sendMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp) { }
+    WebServiceWorkerError(ErrorType errorType, const WebString& message)
+        : errorType(errorType), message(message) { }
+
+    ErrorType errorType;
+    WebString message;
 };
 
 } // namespace WebKit
 
-#endif // WebMIDIAccessor_h
+#endif