<!-- Please describe your changes on the following line: -->
- [X] renamed file SharedMouseAndKeyboardEventInit,
- [X] changed SharedKeyboardAndMouseEventInit to EventModifierInit.
- [X] Rebased mozilla/master into it.
- [x] Ran build and tidy test without errors
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<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#11611 (github issue number if applicable).
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
Source-Repo: https://github.com/servo/servo
Source-Revision: 9e010a8aec7f99fd15bf6334f84c39a3229d115f
