Unassign myself since I'm leaving the team. I heard David and Jinsuk are working in this area.

Jinsuk, would you be able to look into this?

Assigning to wychen who showed interest - wychen could you take a look? Thanks!

This becomes feasible as  Issue 671401  is resolved.

One question to answer about refactoring this is how we model drag event class in the native. EventForwarder/ViewAndroid has been built around MotionEvent only. ui/event doesn't have a class for drag&drop. Should we start with introducing a new event for drag and drop first, or just make use of MotionEvent by adding a few more fields in it?

wychen@ let me know if you will be working on this or not.

aura uses this:
https://cs.chromium.org/chromium/src/ui/base/dragdrop/drop_target_event.h?q=ui::DropTargetEvent&sq=package:chromium

ui/base, not ui/event though. I guess should investigate if it can be shared

I'm focusing on other things for now, so I won't be working on this one for at least a month. Sorry for holding it for too long.

remove this from webview bugcop queue

Great. DropTargetEvent will work if we add os_exchange_data_provider_android.cc that contains the filtered mime types. 

Further look into DropTargetEvent class shows it is suitable only for the action ACTION_DROP (as its name suggests) among the ones Android android.view.DragEvent can have (ACTION_DRAG_{ENTERED|EXITED|ENDED|STARTED|LOCATION}). Other platforms handles these action in separate methods by inheriting DragDropDelegate (ui/aura/client/drag_drop_delegate.h) but it doesn't look handy to make use of the interface on Android since all the info better remain parceled in one event class until it reaches the class (WebContentsViewAndroid) where appropriate action is taken (OnDragEntered/Updated/PerformDrop...etc).

So that makes me think a better way is to define a new event class (inherited from LocatedEvent) that can hold any of these actions plus other info to carry them through ViewAndroid hierarchy. That would make the way drag event is handled analogous to other kinds of events.
 

r474947