[EoS] Connect ExploreSitesBridge to the ExploreSitesService

This actually calls ExploreSitesService::GetCatalog when the request
comes in from the bridge.  Also adds methods for converting the native
objects to Java.

Bug: 867488
Change-Id: Ideee8134ca7947ad95423485655441c3b55d77a7
Reviewed-on: https://chromium-review.googlesource.com/1228312
Reviewed-by: Cathy Li <chili@chromium.org>
Commit-Queue: Justin DeWitt <dewittj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591795}
8 files changed