Adds several ResultDB-related tools to the depot_tools MCP server.
Specifically:
* get_non_exonerated_unexpected_results_from_build which gets all test
results from a build that a normal user would consider failures.
* expand_summary_html which is used to expand the summaryHtml field
included in a ResultDB result to include referenced artifact content.
* get_test_level_text_artifact which retrieves the content of a test
result level text artifact.
Together, these allow Gemini to perform some rudimentary test failure
analysis such as grouping related failures together.
Bug: 438226961
Change-Id: I81cd798d7568bb47b1aa476589816253e29a5630
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6842578
Reviewed-by: Struan Shrimpton <sshrimp@google.com>
Commit-Queue: Struan Shrimpton <sshrimp@google.com>
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>