Mobile perf tests seem to be broken in newer versions

[liyuqian]

When Flutter tries to roll from the old version a208eac to the new version 9eb1ff8, following tests start to fail

• new_gallery_transition_perf
• new_gallery_ios__transition_perf

The log seems to suggest that some scrolling failed.

stdout: [        ] 00:15 �[32m+1�[0m�[31m -1�[0m: Flutter Gallery transitions all demos �[1m�[31m[E]�[0m�[0m
2020-08-28T13:44:18.275690: stdout: [   +1 ms]   DriverError: Failed to fulfill Scroll due to remote error
stdout: [        ]   Original error: Bad state: The client closed with pending request "ext.flutter.driver".

The Crane test doesn't fail so presumably some other parts failed.

See also flutter/flutter#64824 for the context.

[liyuqian]

CC @guidezpl

[guidezpl]

I think the root cause is a workaround was removed for flutter/flutter#64432 (and the previous attempt) to land. The Internal tests are still failing for the reland, so 2 options.

1. Wait until this relands, with the mobile tests failing until then
2. Revert Remove isolates workaround #256, roll gallery version to latest, and un-revert (with no Gallery version rolls until the aforementioned PR relands)

[liyuqian]

Since flutter/flutter#64432 is actively being worked on, let's choose option 1 for now as the mobile tests would still pass in Flutter if we don't roll the gallery version.

We can recheck this issue in 1 week and see if flutter/flutter#64432 is merged. If so, we can close this issue and roll the Gallery version. Otherwise, we can choose option 2 by then.

[guidezpl]

Sounds good, I agree

[liyuqian]

flutter/flutter#64432 landed but got reverted again. Would you like to proceed with option 2?

[guidezpl]

There's a separate PR that looks like it will close the issue flutter/flutter#65703. Let's see if this one sticks

[guidezpl]

That PR has landed 🎉 so I think we can close this issue

[liyuqian]

Cool, I'm going to close this and roll the gallery version in Flutter repo.