[Temp] Backport Chromium r236822.

This is required for XWALK-454 and should help with out-of-source Tizen
builds: after M32 we generate all build system-related files outside the
source tree, and the path to the linker needs to be absolute for that to
work.

Original commit message:

  Pass the gold binary to the linker using only absolute paths.

  The previous expansion using <(PRODUCT_DIR)/../.. did not work correctly
  if one was using a different build directory layout (out-of-source builds,
  or some build directory with a different number of subdirectories).

  Solve this by doing the same as the sysroot variables: stop using relative
  paths from the build directory and extract absolute paths using DEPTH.

  TEST=./build/gyp_chromium -Goutput_dir=/somewhere/else
  R=phajdan.jr@chromium.org,thakis@chromium.org,dpranke@chromium.org

  Review URL: https://codereview.chromium.org/83673002

BUG=https://crosswalk-project.org/jira/browse/XWALK-454
Merge pull request #89 from rakuco/cr-backport-r326822

[Temp] Backport Chromium r236822.