feat: support use selection for find on macOS

[anyerqi]

Description of Change

Chromium has supported Use Selection for Find on macOS, which is commonly-available feature across macOS apps
The changes are:

• add a menu role useSelectionForFind with Command-E as the standard keyboard shortcut
• add a default Edit > Use Selection for Find menu on macOS
• useSelectionForFind maps to copyToFindPboard action

Fixes #29635

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation, tutorials, templates and examples are changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

notes: Added a menu role on macOS: useSelectionForFind

[codebytere]

Can you talk a little about what use cases you're hoping to enable here? I understand Chromium makes use of it, but on Chromium for example it is part of a greater set of find-related menu items, none of which we support as bespoke menu item roles:

Given we've previously merged some Chromium-specific menu roles, I think we're open to this, but would we want to support any other commands in that menu?

[anyerqi]

Use Selection for Find is a common function in apps on MacOS, such as Mail, Safari. In addition, Electron-based VSCode also implements this function by itself. So we can speculate that there must be many other apps that also need this feature. This function is not only effective within the app, it will be passed across apps, you can use it in A app, and then use Find Next in B app. Although there is already an API that allows developers to implement similar function themselves, I think it is more convenient to provide it directly.

For the other commands about Finding, I found that implementing these features in chromium would require a lot of extra work and possibly UI components, but pre-defining the UI in ELectron is not appropriate. In addition, as to which content can be searched and selected, different apps may be different, and there are no uniform rules for Finding

[itsananderson]

The clipboard module already has APIs to read and write to the Find Pasteboard, so I think individual apps could use those APIs to implement their own version of this behavior.

In Chrome, the Use Selection for Find menu item actually opens UI widget to begin a search, whereas I think what you have here would only copy the current selection to the Find Pasteboard, which makes the Use Selection for Find menu name seem misleading. Please correct me if I'm misinterpreting what this new menu item does.

If we were to add any new API surface here, perhaps we could add an API on webContents to make it easier to fetch the current text selection. Otherwise I think currently one would need to run something like the following to fetch the selection, when running from the Main process.

const selectionText = await window.webContents.executeJavaScript('window.getSelection().toString()')
clipboard.writeFindText(selectionText)

[anyerqi]

OK, I understand, I will close this PR