Add sqlite3_shadow_table_fuzzer

This fuzzer will test sqlite3 FTS3 shadow tables and related functions
by implementing a custom structure aware fuzzing. It will try to
generate some grammatical correct queries to manipulate shadow tables,
or to execute some built-in functions of FTS3 to find memory corruption
vulnerabilities.

Bug: 1025467
Change-Id: I809fe02efd43449bee8a072e490309175e533d6f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1924174
Commit-Queue: Matthew Denton <mpdenton@chromium.org>
Reviewed-by: Matthew Denton <mpdenton@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Darwin Huang <huangdarwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719107}

AUTHORS

@@ -1109,3 +1109,4 @@ Vivaldi Technologies AS <*@vivaldi.com>
 Yandex LLC <*@yandex-team.ru>
 Make Positive Provar Limited <*@provartesting.com>
 Jiaxun Wei <leuisken@gmail.com>
+Wenxiang Qian <leonwxqian@gmail.com>

third_party/sqlite/BUILD.gn

@@ -493,6 +493,19 @@ fuzzer_test("sqlite3_fts3_lpm_fuzzer") {
   ]
 }
 
+fuzzer_test("sqlite3_shadow_table_fuzzer") {
+    sources = [
+       "fuzz/shadow_table_fuzzer.cc",
+    ]
+    deps = [
+      ":sqlite",
+    ]
+    additional_configs = [
+      ":sqlite_warnings",
+    ]
+}
+
+
 fuzzer_test("sqlite3_select_printf_lpm_fuzzer") {
   sources = [
     "fuzz/sql_printf_fuzzer.cc",