Revert "Migrate IME service off Service Manager"

This reverts commit 17c7174bc00f980928b810c722e7b942979ce795.

Reason for revert: This appears to have been causing intermittent(!) build failures on Linux ChromiumOS MSan Builder. See https://ci.chromium.org/p/chromium/builders/ci/Linux%20ChromiumOS%20MSan%20Builder/14755 for apparent first example. This may also be responsible for failures on linux-chromeos-rel, see https://ci.chromium.org/p/chromium/builders/ci/Linux%20ChromiumOS%20MSan%20Builder/14755 for an example.

Original change's description:
> Migrate IME service off Service Manager
> 
> This changes the browser's ImeServiceConnector to launch its own service
> process for the IME service and removes all dependency on Service
> Manager APIs from the service and client.
> 
> Adds a new primordial mojom.ImeService interface to control the service,
> allowing for injection of a PlatformAccessProvider and binding of
> arbitrarily many InputEngineManager endpoints.
> 
> NOPRESUBMIT=true
> 
> Bug: 977637
> Change-Id: I2dfb2d55144de114f498d231719136629c71d0cd
> Tbr: shuchen@chromium.org
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1742691
> Commit-Queue: Ken Rockot <rockot@google.com>
> Reviewed-by: Sam McNally <sammc@chromium.org>
> Reviewed-by: Leo Zhang <googleo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#685832}

TBR=rockot@google.com,shuchen@chromium.org,sammc@chromium.org,googleo@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 977637
Change-Id: If9c51ed0f7fa675c3445a3434d09430693dbe3be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1747489
Reviewed-by: Fergus Dall <sidereal@google.com>
Cr-Commit-Position: refs/heads/master@{#685903}
26 files changed