Add a [rtc_]build_with_neon variable to unify conditions.

webrtc/common_audio/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")
@@ skipping 112 matching lines @@
     }
   }
 
   if (current_cpu == "arm") {
     sources += [
       "signal_processing/complex_bit_reverse_arm.S",
       "signal_processing/spl_sqrt_floor_arm.S",
     ]
 
     if (arm_version >= 7) {
-      deps += [ ":common_audio_neon" ]
       sources += [ "signal_processing/filter_ar_fast_q12_armv7.S" ]
     } else {
       sources += [ "signal_processing/filter_ar_fast_q12.c" ]
     }
   }
 
-  if (current_cpu == "arm64") {
+  if (rtc_build_with_neon) {
     deps += [ ":common_audio_neon" ]
   }
 
   if (current_cpu == "mipsel") {
     sources += [
       "signal_processing/complex_bit_reverse_mips.c",
       "signal_processing/complex_fft_mips.c",
       "signal_processing/cross_correlation_mips.c",
       "signal_processing/downsample_fast_mips.c",
       "signal_processing/filter_ar_fast_q12_mips.c",
@@ skipping 53 matching lines @@
     configs += [ "..:common_inherited_config" ]
 
     if (is_clang) {
       # Suppress warnings from Chrome's Clang plugins.
       # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
       configs -= [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }
 
-if (rtc_build_armv7_neon || current_cpu == "arm64") {
+if (rtc_build_with_neon) {
   source_set("common_audio_neon") {
     sources = [
       "fir_filter_neon.cc",
       "resampler/sinc_resampler_neon.cc",
       "signal_processing/cross_correlation_neon.c",
       "signal_processing/downsample_fast_neon.c",
       "signal_processing/min_max_operations_neon.c",
     ]
 
-    configs += [ "..:common_config" ]
-    public_configs = [ "..:common_inherited_config" ]
-
-    if (!arm_use_neon) {
+    if (current_cpu != "arm64") {

[Andrew MacDonald, 2015/06/17 22:46:21]

It unfortunately isn't possible to extract these options to a config. configs
only allow additive changes and can't affect other configs.

+      # Enable compilation for the NEON instruction set. This is needed
+      # since //build/config/arm.gni only enables NEON for iOS, not Android.
+      # This provides the same functionality as webrtc/build/arm_neon.gypi.
       configs -= [ "//build/config/compiler:compiler_arm_fpu" ]
       cflags = [ "-mfpu=neon" ]
     }
 
-    # Disable LTO in audio_processing_neon target due to compiler bug.
+    # Disable LTO due to compiler bug.
     if (rtc_use_lto) {
       cflags -= [
         "-flto",
         "-ffat-lto-objects",
       ]
     }
+
+    configs += [ "..:common_config" ]
+    public_configs = [ "..:common_inherited_config" ]
   }
 }