[Impeller] Improve the performance of text rendering

[zanderso]

Explore performance improvements so that text rendering in Impeller matches the performance of Skia. The techniques used by Skia are likely to translate well over to Impeller.

[chinmaygarde]

All the work items for the meta-bug have been filed and tracked in their own milestone for iOS. Closing this one. For reference, the bugs are listed below. They were discussed during the weekly sync.

• [Impeller] Implement path based text rendering. #112213
• [Impeller] Partially update and reuse glyph atlases across render passes. #116815
• [Impeller] Color and monochrome glyphs should get their own atlases. #116818
• [Impeller] Glyphs rendered using SDF are rendered into their atlases at-scale. #116819
• [Impeller] Devise a strategy for switching between SDF, path-based, and atlas based glyph rendering. #116820

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.