SDK-15417 Performance issue with AIR Flex DragManager
SDK-19249 NativeDragManager calls DragSource handler function too soon
Instead of copying the data from the Clipboard to the DragSource (and back), we now pass in a function handler which delays copying the data until it is needed. I created a new helper class called DragDataFormatFetcher. I used this approach instead of using function closures because function closures have a high instantiation and memory cost.
QE Notes: Add tests to check that the data is not accessed until the user requests it
Doc Notes: none
Bugs: SDK-15417, SDK-19249
Reviewer: Hans, Alex