T310408 identified an issue in the TextInput component (and, therefore, TypeaheadSearch) where the icons were 1px off from being centered within the input padding because we were positioning the icons relative to the inside of the input, rather than the outside of the input's border, which is where they actually get positioned from. This was fixed for TextInput in this patch.
We should review the other components that use this mixin to see if this issue exists elsewhere. If so, we could either:
- Do what we did for TextInput and account for the border's width in the component implementing the mixin
- Account for the border width in the mixin itself, allowing components to pass in the border width (since it might vary)