[google_maps_flutter] Implement polyline patterns in google maps ios

[Hari-07]

This PR Implements patterns in google maps ios polylines. Currently the patterns param is simply ignored on ios, despite the official google maps SDK for ios having instructions on how to achieve repeated patterns: https://developers.google.com/maps/documentation/ios-sdk/shapes#add-a-repeating-color-pattern-to-a-polyline

List which issues are fixed by this PR. You must list at least one issue.
flutter/flutter#60083

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Nil

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[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact "@test-exemption-reviewer" in the #hackers channel in Chat (don't just cc them here, they won't see it! Use Discord!).

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[Hari-07]

I don't currently have any tests, however that is because looking at the existing tests, since I only made changes to the ios package, it didn't seem right to author tests in the google_maps_flutter package.

But looking at tests in google_maps_flutter_ios it seemed like they do not test things like what this PR covers

Open to authoring tests, if someone could let me know what the tests should test

[stuartmorgan-g]

Marking as a draft for now since this needs native unit tests before it will be ready for review (per discussion in Discord).

[Hari-07]

I implemented tests for 2 out of 3 functions I wrote. For the 3rd function, the test should look something like

- (void)testStrokeStylesFromPatterns {
    NSArray* patterns = @ [@[@"gap", @10], @[@"dash", @10]];
    UIColor* strokeColor = [UIColor redColor];
    
    NSArray<GMSStrokeStyle*> *patternStrokeStyle = [FLTGoogleMapJSONConversions strokeStylesFromPatterns:patterns strokeColor:strokeColor];
    
    XCTAssertEqual([patternStrokeStyle count], 2);
    
    GMSStrokeStyle* firstStrokeStyle = patternStrokeStyle[0];
    GMSStrokeStyle* secondStrokeStyle = patternStrokeStyle[1];
    
    // XCTAssertEqualObjects(firstStrokeStyle, [GMSStrokeStyle solidColor:[UIColor clearColor]]);
    // XCTAssertEqualObjects(secondStrokeStyle, [GMSStrokeStyle solidColor:strokeColor]);
}

However, the color property is not readable so I couldn't get this to work.

[stuartmorgan-g]

@Hari-07 Is this ready for review again?

[Hari-07]

I've updated for all your comments other than this thread. Have left a comment on that too.

Apologies about the delay

[Hari-07]

One of the test failure is that the new _Test header isn't in the umbrella header. Do we need to put test headers into it tho?

[stuartmorgan-g]

One of the test failure is that the new _Test header isn't in the umbrella header. Do we need to put test headers into it tho?

Yes, unfortunately the way our builds are structured we have to make the test headers public currently. (Longer term, moving to Swift will resolve this problem.)

[stuartmorgan-g]

Just minor nits, other than that, LGTM once it passes CI!

[Hari-07]

@stuartmorgan Thank you so much for the detailed reviews, and the back and forth. This was a long one. I didn't have prior experience with Obj-C and was figuring it out as we went hence the many beginner mistakes.

Have fixed your latest round of suggestions as well, the only CI failure is its expecting a changelog change in google_maps_flutter but as per this conversation that's not required.

Hope this can get merged in soon 🙏

[stuartmorgan-g]

CHANGELOG override: updating non-main examples to not check for iOS in other packages doesn't warrant client-facing commenting.

[stuartmorgan-g]

LGTM, thanks!