Document Handler API: Changes

The following header file(s) have changed between 3.0 and 3.1

**Table 1:** documenthandler.h
Type	Class	Change
New public method	`CDocumentHandler`	`TBool CanHandleProgressivelyL(const TDataType& aDataType, TUid& aUid);`

The following header file(s) have changed between 3.1 and 3.2

**Table 2:** documenthandler.h
Type	Class	Change
New public method	`CDocumentHandler`	`IMPORT_C void GetProgressiveDownloadAppUidsL( RArray & aUidList );`