Expand simple shape path optimization logic and move it from dl_dispatcher to dl_builder

[b-luk]

Copies the rect/rrect/oval/line path optimization logic from impeller::DlDispatcherBase::SimplifyOrDrawPath to DisplayListBuilder::DrawPath.

impeller::DlDispatcherBase::drawShadow still uses impeller::DlDispatcherBase::SimplifyOrDrawPath, so it can't be completely removed.

The new logic in DisplayListBuilder::DrawPath is expanded to include rects that are open and filled, and to include rrects with non-uniform corner radii. This makes it match Skia graphite's path simpliifcation logic.

This allows many common Paths to be drawn with simpler shapes rather than drawPath, helping with #183044.

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Code Review

This pull request refactors the path drawing logic by moving shape simplification from DlDispatcherBase::drawPath to DisplayListBuilder::DrawPath. The DisplayListBuilder::DrawPath method now attempts to identify and draw simple shapes like rectangles, round rectangles, ovals, and lines using dedicated drawing functions for potential optimization, falling back to general path drawing for more complex paths. A review comment suggests declaring the rect variable for oval bounds within a narrower scope in dl_builder.cc to improve clarity and adhere to the Google C++ Style Guide.

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Golden file changes have been found for this pull request. Click here to view and triage (e.g. because this is an intentional change).

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Changes reported for pull request #184096 at sha 097d227

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Golden file changes are available for triage from new commit, Click here to view.

For more guidance, visit Writing a golden file test for package:flutter.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

Changes reported for pull request #184096 at sha 8b0bd5a

[gaaclarke]

lgtm! thanks

[flar]

The goldens all come from platforms that still use Skia by default I think? It will be interesting what Google testing turns up - potentially a lot of scuba changes as I think most of their golden tests still go through Skia.

I looked at a few of them and they seemed acceptable, but there may be quite a lot of them to triage later during the google roll.

DrawShadow still uses paths only, but I'm not sure it buys us much by testing for shape types in the Builder and increasing the number of DrawShadow ops recorded in the DL buffer.

[flar]

LGTM