Add AccessibilityCharInfo in pdf/ to replace usage of
PP_PrivateAccessibilityCharInfo.
PP_PrivateAccessibilityCharInfo is a Pepper struct. The new struct
ensures that PP_PrivateAccessibilityCharInfo is scoped to parts
specific to Pepper implementation.
Bug: 1144444
Change-Id: I55ab25fd01a8b49976f936688a35de0ada1192a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2554255
Commit-Queue: Ankit Kumar 🌪️ <ankk@microsoft.com>
Reviewed-by: Daniel Hosseinian <dhoss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830490}