[GID] Adjust ToolbarManager API to allow updating image of experimental button.

Experimental button on Toolbar will be used to display profile image,
obtained from ProfileDataCache. This CL adjusts ToolbarManager API to
accep Drawable as an image instead of resource id and to allow updating
the image when it is downloaded.

BUG=958982
R=twellington@chromium.org

Change-Id: Iebc186be316200f696212d410ab6b6319d46c644
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1592683
Commit-Queue: Pavel Yatsuk <pavely@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658227}
4 files changed