[sqlite] sql::Recovery working under USE_SYSTEM_SQLITE.

third_party/sqlite/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 declare_args() {
   # Controls whether the build should uses the version of sqlite3 library
   # shipped with the system (currently only supported on iOS) or the one
   # shipped with Chromium source.
   use_system_sqlite = is_ios
 }
@@ skipping 207 matching lines @@
       libs = [ "sqlite3" ]
     } else {
       assert(false, "extra flags to use system sqlite3 library missing")
     }
   }
 
   source_set("sqlite") {
     public_configs = [ ":sqlite_config" ]
     if (is_ios) {
       deps = [
+        ":sqlite_recover",

[Scott Hess - ex-Googler, 2016/03/10 18:14:50]

This change was obviously suggested from the sqlite.gyp difference, but AFAICT
it didn't actually matter because gn calculated differences correctly. 
Unfortunately trybots and commit-queue don't consider gn on ios, apparently, and
I had only tested gn on Linux where I couldn't get use_system_sqlite to work. 
So...

         ":sqlite_regexp",
       ]
     }
   }
 
   if (is_ios) {
+    source_set("sqlite_recover") {
+      sources = [
+        # TODO(shess): Move out of the SQLite source tree, perhaps to ext/.
+        "src/src/recover.c",
+        "src/src/recover.h",
+        "src/src/recover_varint.c",
+      ]
+    }
+
     source_set("sqlite_regexp") {
       defines = [
         # Necessary to statically compile the extension.
         "SQLITE_CORE",
         "SQLITE_ENABLE_ICU",
         "SQLITE_ENABLE_MEMORY_MANAGEMENT",
       ]
       sources = [
         "src/ext/icu/icu.c",
       ]
       deps = [
         "//third_party/icu",
       ]
       if (is_clang) {
         # src/ext/icu/icu.c uses assert(!"string") which causes warnings about
         # conversion from string literal to bool.
         configs -= [ "//build/config/clang:extra_warnings" ]
       }
     }
   }
 }