GitLab

For boxing purposes this CL moves the history_popup classes into a 
subdirectory of its own, this way boxing this component will be 
easier. 

Bug: 
Change-Id: If652c9ab145fd268231fee538bfbde048a2a40e4
Reviewed-on: https://chromium-review.googlesource.com/595224
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491234}