sqlite: Add SQLITE_OMIT_EXPLAIN and SQLITE_OMIT_REINDEX.

Disable two SQLite features that aren't used in Chrome, saving 9KB of
binary size.

Change-Id: I87ff8c454eed8fe554a6ba93f3cc28d10b91258e
Reviewed-on: https://chromium-review.googlesource.com/c/1341492
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Joshua Bell <jsbell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612931}

third_party/blink/web_tests/storage/websql/test-authorizer-expected.txt

@@ -21,7 +21,7 @@ SQLITE_ALTER_TABLE statement succeeded.
 SQLITE_TRANSACTION statement failed: could not prepare statement (23 not authorized)
 SQLITE_ATTACH statement failed: could not prepare statement (23 not authorized)
 SQLITE_DETACH statement failed: could not prepare statement (23 not authorized)
-SQLITE_REINDEX statement succeeded.
+SQLITE_REINDEX statement failed: could not prepare statement (1 near "REINDEX": syntax error)
 SQLITE_ANALYZE statement failed: could not prepare statement (23 not authorized)
 SQLITE_DROP_INDEX statement succeeded.
 SQLITE_DROP_TEMP_TABLE statement succeeded.
@@ -60,7 +60,7 @@ SQLITE_ALTER_TABLE statement failed: could not prepare statement (23 not authori
 SQLITE_TRANSACTION statement failed: could not prepare statement (23 not authorized)
 SQLITE_ATTACH statement failed: could not prepare statement (23 not authorized)
 SQLITE_DETACH statement failed: could not prepare statement (23 not authorized)
-SQLITE_REINDEX statement failed: could not prepare statement (23 not authorized)
+SQLITE_REINDEX statement failed: could not prepare statement (1 near "REINDEX": syntax error)
 SQLITE_ANALYZE statement failed: could not prepare statement (23 not authorized)
 SQLITE_DROP_INDEX statement failed: could not prepare statement (23 not authorized)
 SQLITE_DROP_TEMP_TABLE statement failed: could not prepare statement (23 not authorized)

third_party/sqlite/BUILD.gn

@@ -114,6 +114,13 @@ config("chromium_sqlite3_compile_options") {
     # Chrome does not use sqlite3_column_decltype().
     "SQLITE_OMIT_DECLTYPE",
 
+    # EXPLAIN's output is not stable across releases [1], so it should not be
+    # used in Chrome. Skipping the EXPLAIN machinery also results in
+    # non-trivial binary savings.
+    #
+    # [1] https://www.sqlite.org/lang_explain.html
+    "SQLITE_OMIT_EXPLAIN",
+
     # Chrome does not use sqlite3_{get,free}_table().
     "SQLITE_OMIT_GET_TABLE",
 
@@ -127,6 +134,15 @@ config("chromium_sqlite3_compile_options") {
     # Chrome doesn't use TCL variables.
     "SQLITE_OMIT_TCL_VARIABLE",
 
+    # The REINDEX statemnt is only useful if a collation sequence's definition
+    # changes [1]. Chrome never defines its own collation sequences [2, 3], so
+    # it never needs to call REINDEX.
+    #
+    # [1] https://www.sqlite.org/lang_reindex.html
+    # [2] https://www.sqlite.org/datatype3.html#collating_sequences
+    # [3] https://www.sqlite.org/c3ref/create_collation.html
+    "SQLITE_OMIT_REINDEX",
+
     # Chrome doesn't use sqlite3_{profile,trace}().
     "SQLITE_OMIT_TRACE",
 

third_party/sqlite/scripts/generate_amalgamation.sh

@@ -10,7 +10,7 @@ mkdir bld
 cd bld
 ../configure
 
-OPTS="-DSQLITE_OMIT_UPSERT -DSQLITE_OMIT_WINDOWFUNC"
+OPTS="-DSQLITE_OMIT_EXPLAIN -DSQLITE_OMIT_REINDEX -DSQLITE_OMIT_UPSERT -DSQLITE_OMIT_WINDOWFUNC"
 make "OPTS=$OPTS" shell.c sqlite3.h sqlite3.c
 cp -f sqlite3.h sqlite3.c ../../amalgamation