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This CL shrinks the Linux binary by 34KB (138,266,816 to 138,232,320).
Code savings aside, this makes sure we don't unintentionally start
depending on these features.

The following compile-time options are recommended in the SQLite
documentation [1]:

* SQLITE_LIKE_DOESNT_MATCH_BLOBS - The LIKE and GLOB operators don't
  work on BLOB columns. This access pattern would be a performance
  wrench, so it's nice to fail hard here.
* SQLITE_OMIT_DEPRECATED - This removes support for deprecated SQLite
  APIs. Note that SQLite promises to maintain indefinite backwards
  compatbility for SQL queries (modulo features disabled via
  compile-time options), so this only applies to the SQLite API. We
  should never be using deprecated APIs.
* SQLITE_OMIT_PROGRESS_CALLBACK - Remove sqlite3_progress_handler(). We
  don't use this feature, and the documentation says it comes with a
  small performance penalty.
* SQLITE_OMIT_SHARED_CACHE - Using a shared cache sounds nice from a
  memory consumption standpoint, and we already do that for LevelDB.
  Unfortunately, Chromium's SQLite databases use a variety of page
  sizes, which makes cache sharing impossible.
* SQLITE_USE_ALLOCA - Use alloca() instead of malloc() for allocating
  temporary spaces in functions. All of Chrome's platforms support this
  option, and it results in a slightly smaller binary and less heap churn.

The following compile-time options disable features that happen not to
be used.

* SQLITE_OMIT_AUTOINIT: We initialize SQLite manually in //sql/connection.cc.
* SQLITE_OMIT_AUTORESET: We calls sqlite3_reset() correctly to reset prepared
  statements.
* SQLITE_OMIT_GET_TABLE: We don't use sqlite3_{get,free}_table().
* SQLITE_OMIT_LOAD_EXTENSION: We don't use sqlite3_{enable_}load_extension().
  Asides from the code savings, there's a tiny security benefit to
  knowing that extension loading code is definitely not reachable from WebSQL.
* SQLITE_OMIT_TCL_VARIABLE: We don't use TCL variables.
* SQLITE_OMIT_TRACE: We don't use sqlite3_{profile,trace}().

Bug: 807093
Change-Id: Ie5e59e55dd9b2ed52f7c27682a809c9f7c36d4a3
Reviewed-on: https://chromium-review.googlesource.com/882961
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Chris Mumford <cmumford@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532995}