Resubmit issue 2221103002 to fix the iOS build by declaring the flag in
SkCommonFlags.h

TBR=reed@google.com,caryclark@google.com

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2393643002

Review-Url: https://codereview.chromium.org/2393643002
17 files changed