Remove DISABLE_X86 from build.gn

BUILD.gn

 # Copyright 2014 The LibYuv 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/config/sanitizers/sanitizers.gni")
@@ skipping 69 matching lines @@
   ]
 
    public_configs = [ ":libyuv_config" ]
 
   defines = []
 
   if (!is_ios) {
     defines += [ "HAVE_JPEG" ]
   }
 
-  if (is_msan) {
-    # MemorySanitizer does not support assembly code yet.
-    # http://crbug.com/344505
-    defines += [ "LIBYUV_DISABLE_X86" ]
-  }
-
   deps = [
     "//third_party:jpeg",
   ]
 
   if (use_neon) {
     deps += [ ":libyuv_neon" ]
   }
 
   if (is_nacl) {
     # Always enable optimization under NaCl to workaround crbug.com/538243 .
@@ skipping 17 matching lines @@
     ]
 
     public_configs = [ ":libyuv_config" ]
 
     if (current_cpu != "arm64") {
       configs -= [ "//build/config/compiler:compiler_arm_fpu" ]
       cflags = [ "-mfpu=neon" ]
     }
   }
 }