Fix chromium.swarm canary breakage from r238996; GYP_DEFINES=clang=1 is needed.
Fix chromium.swarm canary breakage from r238996; GYP_DEFINES=clang=1 is needed.

TBR=vadimsh@chromium.org
BUG=

Review URL: https://codereview.chromium.org/106903004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@239025 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build