GN: Move variables from //build_overrides/webrtc.gni to //webrtc/build/webrtc.gni

webrtc/base/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("//build/config/crypto.gni")
 import("//build/config/ui.gni")
 import("../build/webrtc.gni")
 
-import("//build_overrides/webrtc.gni")
-
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
 
 config("rtc_base_approved_all_dependent_config") {
   if (is_mac && !build_with_chromium) {
     libs = [ "Foundation.framework" ]  # needed for logging_mac.mm
   }
 }
@@ skipping 729 matching lines @@
       "java/src/org/webrtc/Logging.java",
       "java/src/org/webrtc/Size.java",
       "java/src/org/webrtc/ThreadUtils.java",
     ]
 
     deps = [
       "//base:base_java",
     ]
   }
 }