Correct abseil dependencies to make it possible to run gn check

//third_party/abseil-cpp is currently excluded from
gn check because of a couple of dependency fails. This patch
tries to fix those.

Most complicated is the dependency to gmock. The code does
include "gmock/gmock.h" which gn will see as a dependency on
//third_party/googletest:gmock.

Bug: 898837
Change-Id: I2c1d33935511e790e1343cb59db11908cf4fab15
Reviewed-on: https://chromium-review.googlesource.com/c/1307497
Commit-Queue: Daniel Bratell <bratell@opera.com>
Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603976}
3 files changed