[camera] Add API support query for image streaming

[liff]

Add API support query, supportsImageStreaming for checking if the camera platform supports image streaming.

As requested on this comment: #8234 (comment)

Attempting to follow the contribution guide wrt. changing federated plugins.

There is no issue to link to, but should I create one?

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages repo does use dart format.)
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style, or this PR is exempt from CHANGELOG changes.
• 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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[stuartmorgan-g]

Thanks for the contribution!

[stuartmorgan-g]

The default should be false, not to throw, so that existing implementations that don't support it will automatically get the right behavior.

[liff]

Changed.

[stuartmorgan-g]

The web and Windows package changes won't be necessary once the base implementation is changed.

[liff]

Removed those changes.

[stuartmorgan-g]

This needs to be wrapped in a method at this layer; clients are not expected to use the platform interface directly.

[liff]

Added a method.

[camsim99]

Android changes LGTM!

[liff]

Android build is failing in Firebase Test Lab, but I don’t seem to have permission to view the results.

[camsim99]

Android build is failing in Firebase Test Lab, but I don’t seem to have permission to view the results.

The Android image streaming test is failing:

java.lang.Exception: ══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞═════════════════
The following assertion was thrown running a test:
'package:camera/src/camera_controller.dart': Failed assertion:
line 488 pos 12: 'supportsImageStreaming()': is not true.
When the exception was thrown, this was the stack:
#2 CameraController.startImageStream (package:camera/src/camera_controller.dart:488:12)
#3 main.<anonymous closure> (file:///b/s/w/ir/x/w/packages/packages/camera/camera/example/integration_test/camera_test.dart:251:24)
<asynchronous suspension>
#4 testWidgets.<anonymous closure>.<anonymous closure> (package:flutter_test/src/widget_tester.dart:189:15)
<asynchronous suspension>
#5 TestWidgetsFlutterBinding._runTestBody (package:flutter_test/src/binding.dart:1027:5)
<asynchronous suspension>
#6 TestWidgetsFlutterBinding._createTestCompletionHandler.<anonymous closure> (package:flutter_test/src/binding.dart:824:12)
<asynchronous suspension>
(elided 2 frames from class _AssertionError)
The test description was:
Android image streaming
═════════════════════════════════════════════════════════════════
at dev.flutter.plugins.integration_test.FlutterTestRunner.run(FlutterTestRunner.java:84)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:56)
at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:392)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2361)

[liff]

I am unable to reproduce the failure locally with an emulator or with Firebase Test Lab.

I tried the integration tests with Firebase Test Lab both in camera/example and camera_android/example:

$ pushd android
$ ./gradlew app:assembleAndroidTest
$ ./gradlew app:assembleDebug -Ptarget=integration_test/camera_test.dart
$ popd
$ gcloud firebase test android run --type instrumentation --app build/app/outputs/apk/debug/app-debug.apk --test build/app/outputs/apk/androidTest/debug/app-debug-androidTest.apk --timeout 7m --device model=panther,version=33

But I get successful results:

camera_android

┌─────────┬────────────────────────┬─────────────────────┐
│ OUTCOME │ TEST_AXIS_VALUE │ TEST_DETAILS │
├─────────┼────────────────────────┼─────────────────────┤
│ Passed │ panther-33-en-portrait │ 9 test cases passed │
└─────────┴────────────────────────┴─────────────────────┘

camera

┌─────────┬────────────────────────┬─────────────────────┐
│ OUTCOME │ TEST_AXIS_VALUE │ TEST_DETAILS │
├─────────┼────────────────────────┼─────────────────────┤
│ Passed │ panther-33-en-portrait │ 4 test cases passed │
└─────────┴────────────────────────┴─────────────────────┘

and similar results with the emulator, except for this:

Failed assertion: line 89 pos 16: '!(!previousPresetExactlySupported && presetExactlySupported)'

in the “Capture specific image resolutions” test.

Any ideas as to what’s going on?

[liff]

Re-running the check seems to have solved the problem 🎉

[stuartmorgan-g]

The API changes look good to me; this is ready to split out the first sub-PR for landing.

I left notes about missing tests, but those can be addressed in the sub PRs.

[stuartmorgan-g]

This will need a Dart unit test.

[liff]

Included in #8307.

[liff]

Rebased on #8307.

[stuartmorgan-g]

LGTM!