Modify targets under //services/device/public/.

This CL changed //services/device/public/cpp/test:test_support to
//services/device/public/cpp:test_support or conciseness, and merged
separated target ":serial" to the main "mojom" target of services'
public mojo interfaces as it has no special requirement and it's not
a good practice to keep a transitive dependency through public_deps.

Bug: null
Change-Id: I2bcd95e23d6c776f442675b74e2b3d1275ef598d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614425
Commit-Queue: Donna Wu <donna.wu@intel.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662979}
15 files changed