IndexedDB: Rely on bindings for enum validation

Source/modules/indexeddb/IDBIndex.cpp

 /*
  * Copyright (C) 2010 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 68 matching lines @@
         return nullptr;
     }
     if (m_transaction->isFinished() || m_transaction->isFinishing()) {
         exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionFinishedErrorMessage);
         return nullptr;
     }
     if (!m_transaction->isActive()) {
         exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionInactiveErrorMessage);
         return nullptr;
     }
-    WebIDBCursorDirection direction = IDBCursor::stringToDirection(directionString, exceptionState);
-    if (exceptionState.hadException())
-        return nullptr;
-
+    WebIDBCursorDirection direction = IDBCursor::stringToDirection(directionString);
     IDBKeyRange* keyRange = IDBKeyRange::fromScriptValue(scriptState->executionContext(), range, exceptionState);
     if (exceptionState.hadException())
         return nullptr;
 
     if (!backendDB()) {
         exceptionState.throwDOMException(InvalidStateError, IDBDatabase::databaseClosedErrorMessage);
         return nullptr;
     }
 
     return openCursor(scriptState, keyRange, direction);
@@ skipping 45 matching lines @@
         return nullptr;
     }
     if (m_transaction->isFinished() || m_transaction->isFinishing()) {
         exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionFinishedErrorMessage);
         return nullptr;
     }
     if (!m_transaction->isActive()) {
         exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionInactiveErrorMessage);
         return nullptr;
     }
-    WebIDBCursorDirection direction = IDBCursor::stringToDirection(directionString, exceptionState);
-    if (exceptionState.hadException())
-        return nullptr;
-
+    WebIDBCursorDirection direction = IDBCursor::stringToDirection(directionString);
     IDBKeyRange* keyRange = IDBKeyRange::fromScriptValue(scriptState->executionContext(), range, exceptionState);
     if (exceptionState.hadException())
         return nullptr;
     if (!backendDB()) {
         exceptionState.throwDOMException(InvalidStateError, IDBDatabase::databaseClosedErrorMessage);
         return nullptr;
     }
 
     IDBRequest* request = IDBRequest::create(scriptState, IDBAny::create(this), m_transaction.get());
     request->setCursorDetails(IndexedDB::CursorKeyOnly, direction);
@@ skipping 103 matching lines @@
 {
     return m_transaction->backendDB();
 }
 
 bool IDBIndex::isDeleted() const
 {
     return m_deleted || m_objectStore->isDeleted();
 }
 
 } // namespace blink