aw: Fix feature switch memory access

StringPiece only holds pointers to another piece of memory. And
FeatureList::SplitFeatureListString explicitly warns the returned
StringPieces point to the argument. So in previous code, if CommandLine
already had enable/disable switches, the saved StringPiece was pointing
to temporary memory.

Bug: 943926
Change-Id: I7c7708dab7e0c81b9568bb1ffa22533fe4bf3b76
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1532341
Commit-Queue: Bo <boliu@chromium.org>
Reviewed-by: Tim Volodine <timvolodine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642527}
4 files changed