[3/3] Remove ServiceManagerConnection in //chrome

ServiceManagerConnection is slated for imminent deletion. This
replaces usage in //chrome/browser with the simpler
GetSystemConnector(). Split out from a much larger CL.

Bug: 904240
Change-Id: I1a88cd366a75c852fa784ba50976ab72b1fb965c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1666893
Commit-Queue: Ken Rockot <rockot@google.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671097}
48 files changed