GitLab

Chrome stores the seed in preferences, but WebView doesn't persist preferences.
WebView must save save seeds separately. Serialize with protos, and add
aw_variations_seed.proto to mirror the fields in VariationsSeedFetcher.SeedInfo.
Since writing might not complete successfully, the file format must make
truncation unambiguous. The proto wire format is such that truncation in the
middle of a field will be detected, but truncation between fields is permitted.
But by requiring in code that all SeedInfo fields are present, any truncated
seed file will fail to load.

BUG=733857

Change-Id: I7f8d787afed83019c2d891aef419cdf7d593b71c
Reviewed-on: https://chromium-review.googlesource.com/1033823
Commit-Queue: Paul Miller <paulmiller@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555281}