cdab07b84a
Resolves https://github.com/flutter/flutter/issues/130947. - Allow for setting the text renderer (`TextRenderContext`) when the `AiksContext` is built. Previously, the text renderer was selected at build time through linking a `TextRenderContext::Create` symbol. - Support using Impeller without a text backend. Throw a clear error when trying to render text if no text backend is present. - Don't track the Impeller context in `TextRenderContext`. Just let the renderer supply its context when generating atlases. - Allow for overriding the `TextRenderContext` for individual Aiks playground tests/goldens.