After r223264, you can no longer drag and drop documents on the Google Drive home screen that shows all your documents. I bisected it down to this revision, but after reviewing the change, I just can't see how this change is actually breaking anything. From my reading, it should only have any actual effect on Mac. As far as a GTK build is concerned, it looks like it just adds an unused member to a few mouse event classes.
The issue is likely that MousrEvent.buttons is exposed to the Web but unimplemented on GTK. It should either get implemented in GTK or unexposed for this port.
Thanks for investigating, Chris!
Hm, looks like WebEventFactory::createWebMouseEvent in Source/WebKit/Shared/gtk/WebEventFactory.cpp is already passing the pressed mouse buttons into the WebMouseEvent constructor. So that looks fine.
The PlatformMouseEvent constructors are not doing so. I'm attaching a patch to fix these constructors as a starting point, but it's not enough to fix Google Drive. Further investigation will be required as to why it's still not working.
Created attachment 354506 [details]
Attachment 354506 [details] did not pass style-queue:
ERROR: Source/WebCore/ChangeLog:8: You should remove the 'No new tests' and either add and list tests, or explain why no new tests were possible. [changelog/nonewtests] 
Total errors found: 1 in 2 files
If any of these errors are false positives, please file a bug against check-webkit-style.
(In reply to Michael Catanzaro from comment #3)
> Hm, looks like WebEventFactory::createWebMouseEvent in
> Source/WebKit/Shared/gtk/WebEventFactory.cpp is already passing the pressed
> mouse buttons into the WebMouseEvent constructor. So that looks fine.
It was implemented in r230988, a good time after r223264, but still a while back.
Backporting this patch into the 2.20 branch that I am working off of does indeed restore drag/drop functionality for Google Drive.
I guess this ticket should be closed as invalid.
No, because it's broken in trunk with or without my patch.
Ok. Just to clarify, as it might help:
I am running off of the 2.20 branch. The drag/drop on Google Drive was broken there. But when I merged in 230988 to the 2.20 branch, everything is working now. This is WITHOUT merging in your attachment to this ticket though.
So maybe there was another commit after the 2.20 branch or after 230988 that rebroke it?