Skip shadow root creation for input types that don't need it

Certain input types like checkboxes and radio buttons don't make use
of the shadow root that is currently created by default. This CL adds
a method to InputTypeView that indicates if an input type needs to
create a shadow root, and skips shadow root creation in
InitializeTypeInParsing if possible.

Change-Id: Id932c06cdd924a5b6006d8770d9cc6d09cb3da82
Commit-Queue: Adithya Srinivasan <>
Reviewed-by: Jeremy Roman <>
Reviewed-by: Kentaro Hara <>
Reviewed-by: Hayato Ito <>
Reviewed-by: Keishi Hattori <>
Cr-Commit-Position: refs/heads/master@{#518955}
20 files changed