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This patch restores the layout trace viewer removed in e7510ab90c , with some changes that makes it work with https://github.com/servo/servo/pull/13214
Sorry for the minified 3rd party CSS frameworks, it was from the original version and I haven't got time to replace them with hand-crafted CSS.
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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
- [ ] These changes fix #__ (github issue number if applicable).
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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because is a stand-alone debugging tool
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Source-Repo: https://github.com/servo/servo
Source-Revision: 0af9be94298c676f5bf7881847880e6f43955602
1a39b2a083
