test: allow use of system gmock/gtest libs

test: allow use of system gmock/gtest libs

Some systems provide prebuilt copies of gmock/gtest (such as Chromium
OS).  Add a configure flag so they can take advantage of that.  This
allows for a smaller checkout as they don't need to include the full
testing/ tree.

BUG=chromium:579384
TEST=`make check` passes w/--enable-system-test-libs
TEST=`make check` passes w/--disable-system-test-libs
R=thestig@chromium.org

Committed: https://chromium.googlesource.com/breakpad/breakpad/+/de54eb133fad11a08396c7698d55a0c22caa4568

[vapier, 2016-01-25 23:48:08]

vapier@chromium.org changed reviewers:
+ mark@chromium.org, thestig@chromium.org

[Lei Zhang, 2016-01-25 23:57:27]

lgtm

[vapier, 2016-01-26 00:28:00]

Description was changed from

==========
test: allow use of system gmock/gtest libs

Some systems provide prebuilt copies of gmock/gtest (such as Chromium
OS).  Add a configure flag so they can take advantage of that.  This
allows for a smaller checkout as they don't need to include the full
testing/ tree.

BUG=chromium:579384
TEST=`make check` passes w/--enable-system-test-libs
TEST=`make check` passes w/--disable-system-test-libs
==========

to

==========
test: allow use of system gmock/gtest libs

Some systems provide prebuilt copies of gmock/gtest (such as Chromium
OS).  Add a configure flag so they can take advantage of that.  This
allows for a smaller checkout as they don't need to include the full
testing/ tree.

BUG=chromium:579384
TEST=`make check` passes w/--enable-system-test-libs
TEST=`make check` passes w/--disable-system-test-libs
R=thestig@chromium.org

Committed:
https://chromium.googlesource.com/breakpad/breakpad/+/de54eb133fad11a08396c76...
==========

[vapier, 2016-01-26 00:28:01]

Committed patchset #1 (id:1) manually as
de54eb133fad11a08396c7698d55a0c22caa4568 (presubmit successful).