[webcrypto] Define the DOMException OperationError.

Source/core/dom/DOMException.cpp

 /*
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 58 matching lines @@
     { "ReadOnlyError", "A write operation was attempted in a read-only transaction.", 0 },
     { "VersionError", "An attempt was made to open a database using a lower version than the existing version.", 0 },
 
     // File system
     { "NotReadableError", "The requested file could not be read, typically due to permission problems that have occurred after a reference to a file was acquired.", 0 },
     { "EncodingError", "A URI supplied to the API was malformed, or the resulting Data URL has exceeded the URL length limitations for Data URLs.", 0 },
     { "PathExistsError", "An attempt was made to create a file or directory where an element already exists.", 0 },
 
     // SQL
     { "DatabaseError", "The operation failed for some reason related to the database.", 0 },
+
+    // Web Crypto
+    { "OperationError", "The operation failed for an operation-specific reason", 0 },
 };
 
 static const CoreException* getErrorEntry(ExceptionCode ec)
 {
     size_t tableSize = WTF_ARRAY_LENGTH(coreExceptions);
     size_t tableIndex = ec - IndexSizeError;
 
     return tableIndex < tableSize ? &coreExceptions[tableIndex] : 0;
 }
 
@@ skipping 41 matching lines @@
 {
     const CoreException* entry = getErrorEntry(ec);
     ASSERT(entry);
     if (!entry)
         return "Unknown error.";
 
     return entry->message;
 }
 
 } // namespace WebCore