Reland of Moving webrtc.gni up one level from build/

webrtc/modules/video_processing/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/arm.gni")
-import("../../build/webrtc.gni")
+import("../../webrtc.gni")
 
 build_video_processing_sse2 = current_cpu == "x86" || current_cpu == "x64"
 
 rtc_static_library("video_processing") {
   sources = [
     "util/denoiser_filter.cc",
     "util/denoiser_filter.h",
     "util/denoiser_filter_c.cc",
     "util/denoiser_filter_c.h",
     "util/noise_estimation.cc",
@@ skipping 80 matching lines @@
       "../../common_video:common_video",
       "../../test:test_support",
       "../../test:video_test_common",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }