Revert of DEPS: Update leveldatabase from 1.18 to 1.20.

third_party/leveldatabase/BUILD.gn

 # Copyright 2014 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.
 
 import("//testing/test.gni")
 
 defines = [ "LEVELDB_PLATFORM_CHROMIUM=1" ]
 
 config("leveldatabase_config") {
   include_dirs = [
     ".",
     "src",
     "src/include",
   ]
 }
 
-source_set("leveldatabase_opts.sse42") {
-  sources = [
-    "src/port/port_posix_sse.cc",
-  ]
-
-  configs += [ ":leveldatabase_config" ]
-
-  if (target_cpu == "x86" || target_cpu == "x64") {
-    defines += [ "LEVELDB_PLATFORM_POSIX_SSE" ]
-    if (!is_win || is_clang) {
-      cflags = [ "-msse4.2" ]
-    }
-  }
-}
-
 static_library("leveldatabase") {
   sources = [
     "env_chromium.cc",
     "env_chromium.h",
     "port/port_chromium.cc",
     "port/port_chromium.h",
     "src/db/builder.cc",
     "src/db/builder.h",
     "src/db/db_impl.cc",
     "src/db/db_impl.h",
@@ skipping 74 matching lines @@
     "src/util/random.h",
     "src/util/status.cc",
   ]
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 
   public_configs = [ ":leveldatabase_config" ]
 
   deps = [
-    ":leveldatabase_opts.sse42",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//third_party/re2",
     "//third_party/snappy",
   ]
 
   if (is_win) {
     cflags = [ "/wd4018" ]  # Signed/unsigned mismatch in comparison.
 
     if (is_official_build) {
@@ skipping 225 matching lines @@
     ]
 
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [ "//build/config/compiler:no_chromium_code" ]
 
     deps = [
       ":leveldb_testutil",
     ]
   }
 }