Description

This PR is a reland of #30339.

Changes compared with the previous attempt: (See here for diff)

• If a pointer data contains PointerDeviceKind.unknown, PointerEventConverter will synthesize its buttons using the following rule: if buttons = 0, return kPrimaryButton; otherwise return unchanged.
• Changed TestPointer to a better API. Its buttons can no longer be set; instead set it using the new optional parameter in methods down and move.

Explanation

The previous attempt broke some device labs and the desktop embedder. Through investigation, it's likely because adb shell input as well as the desktop embedder send events that have device kind unknown and buttons 0, which was not synthesized with kPrimaryButton. To fix this, this PR synthesizes kPrimaryButton for PointerDeviceKind.unknown.

All red device labs have been manually tested on real Android devices.

Related Issues

• Previous attempt: Add buttons to gestures #30339

Tests

I added the following tests:

• PointerEventConverter should synthesize events from unknown.

Checklist

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Breaking Change

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