Reenable web benchmarks

[ditman]

This PR uses the recently released web_benchmarks: 0.0.7 that supports Chrome 89+ to reenable the web benchmarks here.

There was also a problem in the gallery_automator.dart file, that used dart:io to print output to stdout. dart:io methods cannot be called in a browser, and the benchmarks failed.

I removed the dependency on dart:io from that file, and replaced stdout.writeln by print calls. I had to ignore_for_file:avoid_print because the analyzer thinks that the code I'm touching is "production", when it should be detected as tests.

• Fixes Re-enable web benchmarks #463

This is what I get when I run the benchmarks in my machine (looks good, but I need to run each of the tests separately. If I do flutter test test_benchmarks, there seems to be some race condition that makes the benchmarks to never finish (?):

$ flutter test test_benchmarks/web_bundle_size_test.dart 

01:40 +0: Web Compile bundle size
Shell: 
Shell: Building without sound null safety
Shell: For more information see https://dart.dev/null-safety/unsound-null-safety
Shell: 
Shell: Compiling lib/main.dart for the Web...                             89.3s
01:41 +0: Web Compile bundle size
Shell: 4108	/usr/local/google/home/dit/github/flutter_gallery/build/web/main.dart.js
Shell: 1008	/usr/local/google/home/dit/github/flutter_gallery/build/web/main.dart.js.gz
01:41 +1: All tests passed!

----

$ flutter test test_benchmarks/benchmarks_test.dart 

00:02 +0: Can run a web benchmark
Shell: Starting web benchmark tests ...
01:34 +0: Can run a web benchmark                                                                                                      
Launching Chrome.
Launching Google Chrome 98.0.4758.102 

Waiting for the benchmark to report benchmark profile.
[CHROME]: 
[CHROME]: DevTools listening on ws://127.0.0.1:10000/devtools/browser/6514abc1-d1dd-4d74-9e7e-0f2a8c7d9a1d
Connecting to DevTools: ws://localhost:10000/devtools/page/FD8EBB697EF7C84538458956D5AF5609
Connected to Chrome tab:  (http://localhost:9999/index.html)
Launching benchmark "gallery_v2_studies_perf"
[APP] Warming up.
[APP] Warm-up finished.
[APP] ==== List of demos to be run ====
[APP] shrine@study
[APP] rally@study
[APP] crane@study
[APP] fortnightly@study
[APP] reply@study
[APP] starter@study
[APP] ==== End of list of demos to be run ====
[APP] Running demo "shrine@study"
[APP] Running demo "rally@study"
[APP] Running demo "crane@study"
[APP] Running demo "fortnightly@study"
[APP] Running demo "reply@study"
[APP] Running demo "starter@study"
[APP] All demos finished.
Extracted 572 measured frames.
Skipped 123 non-measured frames.
Launching benchmark "gallery_v2_unanimated_perf"
[APP] Warming up.
[APP] Warm-up finished.
[APP] ==== List of demos to be run ====
[APP] app-bar@material
[APP] banner@material
[APP] bottom-app-bar@material
[APP] bottom-navigation@material
[APP] bottom-sheet@material
[APP] button@material
[APP] card@material
[APP] chip@material
[APP] data-table@material
[APP] dialog@material
[APP] divider@material
[APP] grid-lists@material
[APP] lists@material
[APP] menu@material
[APP] nav_drawer@material
[APP] nav_rail@material
[APP] pickers@material
[APP] selection-controls@material
[APP] sliders@material
[APP] snackbars@material
[APP] tabs@material
[APP] text-field@material
[APP] tooltip@material
[APP] cupertino-alerts@cupertino
[APP] cupertino-buttons@cupertino
[APP] cupertino-context-menu@cupertino
[APP] cupertino-navigation-bar@cupertino
[APP] cupertino-picker@cupertino
[APP] cupertino-pull-to-refresh@cupertino
[APP] cupertino-segmented-control@cupertino
[APP] cupertino-slider@cupertino
[APP] cupertino-switch@cupertino
[APP] cupertino-tab-bar@cupertino
[APP] cupertino-text-field@cupertino
[APP] motion@other
[APP] colors@other
[APP] typography@other
[APP] 2d-transformations@other
[APP] ==== End of list of demos to be run ====
[APP] Running demo "app-bar@material"
[APP] Running demo "banner@material"
[APP] Running demo "bottom-app-bar@material"
[APP] Running demo "bottom-navigation@material"
[APP] Running demo "bottom-sheet@material"
[APP] Running demo "button@material"
[APP] Running demo "card@material"
[APP] Running demo "chip@material"
[APP] Running demo "data-table@material"
[APP] Running demo "dialog@material"
[APP] Running demo "divider@material"
[APP] Running demo "grid-lists@material"
[APP] Running demo "lists@material"
[APP] Running demo "menu@material"
[APP] Running demo "nav_drawer@material"
[APP] Running demo "nav_rail@material"
[APP] Running demo "pickers@material"
[APP] Running demo "selection-controls@material"
[APP] Running demo "sliders@material"
[APP] Running demo "snackbars@material"
[APP] Running demo "tabs@material"
[APP] Running demo "text-field@material"
[APP] Running demo "tooltip@material"
[APP] Running demo "cupertino-alerts@cupertino"
[APP] Running demo "cupertino-buttons@cupertino"
[APP] Running demo "cupertino-context-menu@cupertino"
[APP] Running demo "cupertino-navigation-bar@cupertino"
[APP] Running demo "cupertino-picker@cupertino"
[APP] Running demo "cupertino-pull-to-refresh@cupertino"
[APP] Running demo "cupertino-segmented-control@cupertino"
[APP] Running demo "cupertino-slider@cupertino"
[APP] Running demo "cupertino-switch@cupertino"
[APP] Running demo "cupertino-tab-bar@cupertino"
[APP] Running demo "cupertino-text-field@cupertino"
[APP] Running demo "motion@other"
[APP] Running demo "colors@other"
[APP] Running demo "typography@other"
[APP] Running demo "2d-transformations@other"
[APP] All demos finished.
Extracted 3076 measured frames.
Skipped 131 non-measured frames.
Launching benchmark "gallery_v2_animated_perf"
[APP] Warming up.
[APP] Warm-up finished.
[APP] ==== List of demos to be run ====
[APP] progress-indicator@material
[APP] cupertino-activity-indicator@cupertino
[APP] ==== End of list of demos to be run ====
[APP] Running demo "progress-indicator@material"
[APP] Running demo "cupertino-activity-indicator@cupertino"
[APP] All demos finished.
Extracted 849 measured frames.
Skipped 127 non-measured frames.
Launching benchmark "gallery_v2_scroll_perf"
[APP] Warming up.
[APP] Warm-up finished.
[APP] Running scrolling test.
[APP] Scrolling test finished.
Extracted 388 measured frames.
Skipped 132 non-measured frames.
Received profile data
Shell: Web benchmark tests finished.
03:25 +1: All tests passed!

PS: I think this PR should be text-exempt, since it's reenabling a bunch of benchmarks.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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[ditman]

Tests / Benchmark tests (pull_request) Successful in 8m

All right, this seems to work on the github action! (but it was "flaky" on my machine 😖)

[guidezpl]

Thanks! If this issue pops up again, we may want to avoid concurrent testing of benchmarks in the GitHub Action workflow

[ditman]

Clicking the "Squash and merge" button, @guidezpl feel free to ping me if we need to revisit this!