bdbd0ffdf2
Execute encoding/decoding of clipboard data in background... was seeing a lot of red flashes for large file selections. Move the majority of the Clipboard management code into a shared DocumentClipper class. Hide the copy-to and move-to menus in same. BUG=20915675 Change-Id: Iff59e846afe6f1e90e6be816f5860d8b7efe3ae1