Add --test-type flag

[natebosch]

Closes #2300

Some flags like disabling TimerThrottlingForBackgroundTabs cause
warnings when launching chrome because it is not recommended for use
during general browsing. Suppress these types of warnings with the
--test-type flag which indicates to chrome that this is a dev focused
workflow where such flags are expected.

[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:bazel_worker	1.1.5	already published at pub.dev
package:benchmark_harness	2.4.0	already published at pub.dev
package:boolean_selector	2.1.2	already published at pub.dev
package:browser_launcher	1.2.0-wip	WIP (no publish necessary)
package:cli_config	0.2.1-wip	WIP (no publish necessary)
package:cli_util	0.5.0-wip	WIP (no publish necessary)
package:clock	1.1.3-wip	WIP (no publish necessary)
package:code_builder	4.11.1	already published at pub.dev
package:coverage	1.15.0	already published at pub.dev
package:csslib	1.0.2	already published at pub.dev
package:extension_discovery	2.1.0	already published at pub.dev
package:file	7.0.2-wip	WIP (no publish necessary)
package:file_testing	3.1.0-wip	WIP (no publish necessary)
package:glob	2.1.3	already published at pub.dev
package:graphs	2.3.3-wip	WIP (no publish necessary)
package:html	0.15.7-wip	WIP (no publish necessary)
package:io	1.1.0-wip	WIP (no publish necessary)
package:json_rpc_2	4.1.0-wip	WIP (no publish necessary)
package:markdown	7.3.1-wip	WIP (no publish necessary)
package:mime	2.1.0-wip	WIP (no publish necessary)
package:oauth2	2.0.5	already published at pub.dev
package:package_config	2.3.0-wip	WIP (no publish necessary)
package:pool	1.5.2	already published at pub.dev
package:process	5.0.5	already published at pub.dev
package:pub_semver	2.2.0	already published at pub.dev
package:pubspec_parse	1.6.0-wip	WIP (no publish necessary)
package:source_map_stack_trace	2.1.3-wip	WIP (no publish necessary)
package:source_maps	0.10.14-wip	WIP (no publish necessary)
package:source_span	1.10.1	already published at pub.dev
package:sse	4.1.8	already published at pub.dev
package:stack_trace	1.12.2-wip	(error) pubspec version (1.12.2-wip) and changelog (1.12.2-dev) don't agree
package:stream_channel	2.1.4	already published at pub.dev
package:stream_transform	2.1.2-wip	WIP (no publish necessary)
package:string_scanner	1.4.2-wip	WIP (no publish necessary)
package:term_glyph	1.2.3-wip	WIP (no publish necessary)
package:test_reflective_loader	0.5.0	ready to publish	test_reflective_loader-v0.5.0
package:timing	1.0.2	already published at pub.dev
package:unified_analytics	8.0.13	ready to publish	unified_analytics-v8.0.13
package:watcher	1.2.2-wip	WIP (no publish necessary)
package:yaml	3.1.3	already published at pub.dev
package:yaml_edit	2.2.3	(error) pubspec version (2.2.3) and changelog (2.3.0) don't agree

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[github-actions]

PR Health

License Headers ✔️

// Copyright (c) 2026, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

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Files
pkgs/bazel_worker/benchmark/benchmark.dart
pkgs/benchmark_harness/integration_test/perf_benchmark_test.dart
pkgs/boolean_selector/example/example.dart
pkgs/clock/lib/clock.dart
pkgs/clock/lib/src/clock.dart
pkgs/clock/lib/src/default.dart
pkgs/clock/lib/src/stopwatch.dart
pkgs/clock/lib/src/utils.dart
pkgs/clock/test/clock_test.dart
pkgs/clock/test/default_test.dart
pkgs/clock/test/stopwatch_test.dart
pkgs/clock/test/utils.dart
pkgs/coverage/lib/src/coverage_options.dart
pkgs/html/example/main.dart
pkgs/html/lib/dom.dart
pkgs/html/lib/dom_parsing.dart
pkgs/html/lib/html_escape.dart
pkgs/html/lib/parser.dart
pkgs/html/lib/src/constants.dart
pkgs/html/lib/src/encoding_parser.dart
pkgs/html/lib/src/html_input_stream.dart
pkgs/html/lib/src/list_proxy.dart
pkgs/html/lib/src/query_selector.dart
pkgs/html/lib/src/token.dart
pkgs/html/lib/src/tokenizer.dart
pkgs/html/lib/src/treebuilder.dart
pkgs/html/lib/src/utils.dart
pkgs/html/test/dom_test.dart
pkgs/html/test/parser_feature_test.dart
pkgs/html/test/parser_test.dart
pkgs/html/test/query_selector_test.dart
pkgs/html/test/selectors/level1_baseline_test.dart
pkgs/html/test/selectors/level1_lib.dart
pkgs/html/test/selectors/selectors.dart
pkgs/html/test/support.dart
pkgs/html/test/tokenizer_test.dart
pkgs/html/test/trie_test.dart
pkgs/html/tool/generate_trie.dart
pkgs/pubspec_parse/test/git_uri_test.dart
pkgs/stack_trace/example/example.dart
pkgs/watcher/test/custom_watcher_factory_test.dart
pkgs/yaml_edit/example/example.dart

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Breaking changes ✔️

Package	Change	Current Version	New Version	Needed Version	Looking good?
browser_launcher	None	1.1.3	1.2.0-wip	1.1.3	✔️

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Coverage ✔️

File	Coverage
pkgs/browser_launcher/lib/src/chrome.dart	💚 68 % ⬆️ 1 %

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[gemini-code-assist]

Code Review

This pull request adds the --test-type flag to Chrome launch arguments to suppress certain warnings, which is a useful improvement for development workflows. The associated CHANGELOG.md and pubspec.yaml files have been updated accordingly. My review includes a minor suggestion to improve a comment's readability and adherence to the project's style guide, specifically the Effective Dart guidelines.

[gmpassos]

@natebosch

How about also adding:

--disable-session-crashed-bubble

For developers, if Chrome is closed abruptly (without using the Quit/Close option in the Chrome UI), it shows the “session crashed” bubble on the next launch. Since every launch of a developer Chrome instance is independent of previous sessions, this flag prevents that unnecessary warning.

[natebosch]

How about also adding:

Seems like a good idea. Thanks. #2321