Make build tweaks to support newer libchrome

Android uses a very old version of libchrome and there are several
breaking changes in the latest libchrome. Using BASE_VER defined in the
libchrome provided by ChromeOS, we add a few abstractions:
* AbstractMessageLoop to replace MessageLoop
* AbstractObserverList to replace ObserverList
* Work around ExportedObject::ResponseSender changing from
  base::RepeatingCallback to base::OnceCallback

Also add a few more workarounds for libchrome differences (missing
includes, unresolved symbols, etc).

Bug: 177961465
Tag: #refactor
Test: run --host bluetooth_test_gd
Test: run --host bluetooth_test_common
Change-Id: I94bc3dd4cd86bd357d869f23e95de9e53184696d