tree 1345752e0bfe2c2a549df3dae05d92f3ffd9e6e4
parent 230edb88b12d79f8719562e930fb76ef8229052a
author tim <tim@rnc-ag.de> 1475790342 -0700
committer Commit bot <commit-bot@chromium.org> 1475790435 +0000

GN: Initialize Tool::defined_from_ in the constructor

set_defined_from() isn't called in some tests (e.g. those using TestWithScope),
thus calling defined_from() will only yield garbage, likely leading to a crash.

BUG=

Review-Url: https://codereview.chromium.org/2394323002
Cr-Original-Commit-Position: refs/heads/master@{#423698}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: fb7800730f213aba891c83df31b7183fc4cbcdc5