GitLab

This CL introduces SqlTempStoreMemory flag, which is intended to be
managed via Finch. When set, the flag causes sql::Database to run a
PRAGMA temp_store=MEMORY [1] query on every opened database.

This approach is intended to approximate the effect of building SQLite
with the SQLITE_TEMP_STORE=3 [2] macro, to measure the memory
consumption impact. Ideally, we'd test the macro directly, but //sql is
a core component of Chrome, so we can't load different versions of it
based on Finch.

[1] https://www.sqlite.org/pragma.html#pragma_temp_store
[2] https://www.sqlite.org/compile.html#temp_store

Bug: 875538
Change-Id: I537d90d763be1100503ed4bd2ada2ee19eb090bb
Reviewed-on: https://chromium-review.googlesource.com/1180530Reviewed-by: Mark Pearson <mpearson@chromium.org>
Reviewed-by: Chris Mumford <cmumford@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584652}