[webview_flutter] Add support for js alert, confirm, prompt.

[jerryzhoujw]

Description

Add support for javascript alert, confirm, prompt.

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[jerryzhoujw]

fix 30358

[dieudv]

I see you're only fix for ios. Can you fix for android?

[jerryzhoujw]

@dieudv I'm not familiar with android develop, but I can try to take a look into it later. If anyone who familiar with android would like to fix this would be better.

[amirh]

Thank you for the contribution!

I'm following the initial PR review policy, this PR isn't trivial to review, and the Android counterpart is still massing so I'm labeling it with "backlog" and we will prioritize according to the issue's priority.

[shinriyo]

Is it too difficult to fix for Google developers?
This issue is neglected more than one years since 25 Aug 2019.
Or, is it policy not using alert, confirm and prompt?

[stuartmorgan]

@blasten Is there a policy for changes that only affect Virtual Display mode at this point? I.e., would it be worthwhile for someone to invest time in adding tests for this if (going by the recent comment on the issue) it's not an issue with Hybrid Composition?

[stuartmorgan]

Now that we've switched Android to hybrid composition by default, I don't think there's any reason this couldn't move forward with an iOS-only implementation.

This will need XCUITests added to cover the new functionality; please let us know when those are in place and we can review!

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie on the #hackers channel in Chat.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[Hixie]

@jerryzhoujw Are you still interested in working on this PR?

[jerryzhoujw]

@Hixie, I'm not familiar with android develop. but ok for iOS part.

[stuartmorgan]

I'm not familiar with android develop

As I mentioned above, now that hybrid composition is the default on Android it's fine for this PR to be iOS-only. It just needs to be updated and tested.

[jerryzhoujw]

I'll do it soon.

[stuartmorgan]

Thank you for your contribution. I'm going to close this PR for now since there are outstanding comments, just to get this off our PR review queue. Please don't hesitate to submit a new PR if you have the time to address the review comments. Thanks!