Cookie Store: Remove SQLite special casing for iOS 8.1 and below.

First, Chrome currently requires iOS 10.0 or above. Second, as of
today, Chrome for iOS will use our patched version of SQLite, removing
an unnecessary point of divergence between platforms.

Cq-Include-Trybots: master.tryserver.chromium.mac:ios-device
Change-Id: I365713588d079658d5be9c1282d40f591aba05f7
Reviewed-on: https://chromium-review.googlesource.com/907497Reviewed-by: Randy Smith <rdsmith@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536694}

net/extras/sqlite/sqlite_persistent_cookie_store.cc

@@ -1011,16 +1011,9 @@ bool SQLitePersistentCookieStore::Backend::EnsureDatabaseVersion() {
       return false;
     }
 
-#if defined(OS_IOS)
-    // iOS 8.1 and older doesn't support partial indices. iOS 8.2 supports
-    // partial indices.
-    if (!db_->Execute(
-            "CREATE INDEX IF NOT EXISTS is_transient ON cookies(persistent)")) {
-#else
     if (!db_->Execute(
             "CREATE INDEX IF NOT EXISTS is_transient ON cookies(persistent) "
             "where persistent != 1")) {
-#endif
       LOG(WARNING)
           << "Unable to create index is_transient in update to version 9.";
       return false;