Converter clients can supply a converter observer object
by implementing the MConverterUiObserver interface. The object
is passed to the converter's CConverterBase2::ConvertL(), CConverterBase2::ConvertObjectL(), CConverterBase2::ConvertAL() or CConverterBase2::ConvertObjectAL() function. It is used
for reporting on the progress of multi-step conversions and for requesting
a password from the client when the file being converted from is password-protected.
The following functions can be implemented:
virtual void MaxSteps(TInt aMax, TInt aObject)=0; to
get the maximum number of steps that the conversion operation can take.
virtual TInt Result(TInt aResult, TInt aObject)=0; to
take some action following an error in the conversion.
virtual HBufC* QueryPasswordL(const TDesC& aClue)=0; to
request a password from the user in order to access the data.