Update Chomium's build files to work w/ latest GN binaries.

media/base/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("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/ui.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//media/media_options.gni")
 
@@ skipping 224 matching lines @@
       "//ui/gfx/x",
     ]
   } else if (is_mac) {
     sources += [ "user_input_monitor_mac.cc" ]
   } else if (is_win) {
     sources += [ "user_input_monitor_win.cc" ]
   } else {
     defines += [ "DISABLE_USER_INPUT_MONITOR" ]
   }
 
-  if (cpu_arch == "x86" || cpu_arch == "x64") {
+  if (current_cpu == "x86" || current_cpu == "x64") {
     sources += [ "simd/convert_yuv_to_rgb_x86.cc" ]
     deps += [
       ":media_yasm",
       ":media_sse2",
     ]
   }
 
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   if (is_linux || is_win) {
@@ skipping 110 matching lines @@
       "media_file_checker_unittest.cc",
     ]
   }
 
   if (!is_android) {
     sources += [ "container_names_unittest.cc" ]
   } else {
     deps += [ "//ui/gl" ]
   }
 
-  if (cpu_arch == "x86" || cpu_arch == "x64") {
+  if (current_cpu == "x86" || current_cpu == "x64") {
     sources += [ "simd/convert_rgb_to_yuv_unittest.cc" ]
   }
 }
 
 source_set("perftests") {
   testonly = true
   sources = [
     "audio_bus_perftest.cc",
     "audio_converter_perftest.cc",
     "run_all_perftests.cc",
@@ skipping 11 matching lines @@
 
   if (media_use_ffmpeg) {
     sources += [ "demuxer_perftest.cc" ]
   }
 
   if (is_android) {
     deps += [ "//ui/gl" ]
   }
 }
 
-if (cpu_arch == "x86" || cpu_arch == "x64") {
+if (current_cpu == "x86" || current_cpu == "x64") {
   source_set("media_sse2") {
     sources = [
       "simd/convert_rgb_to_yuv_sse2.cc",
       "simd/convert_rgb_to_yuv_ssse3.cc",
       "simd/filter_yuv_sse2.cc",
     ]
     configs += [ "//media:media_config" ]
     if (!is_win) {
       cflags = [ "-msse2" ]
     }
@@ skipping 26 matching lines @@
     inputs = [
       "//third_party/x86inc/x86inc.asm",
       "simd/convert_rgb_to_yuv_ssse3.inc",
       "simd/convert_yuv_to_rgb_mmx.inc",
       "simd/convert_yuva_to_argb_mmx.inc",
       "simd/linear_scale_yuv_to_rgb_mmx.inc",
       "simd/media_export.asm",
       "simd/scale_yuv_to_rgb_mmx.inc",
     ]
 
-    if (cpu_arch == "x86") {
+    if (current_cpu == "x86") {
       yasm_flags += [ "-DARCH_X86_32" ]
-    } else if (cpu_arch == "x64") {
+    } else if (current_cpu == "x64") {
       yasm_flags += [ "-DARCH_X86_64" ]
       sources += [
         "simd/linear_scale_yuv_to_rgb_mmx_x64.asm",
         "simd/scale_yuv_to_rgb_sse2_x64.asm",
       ]
     }
 
     if (is_mac || is_ios) {
       yasm_flags += [
         "-DPREFIX",
         "-DMACHO",
       ]
     } else {
       if (is_posix) {
         yasm_flags += [ "-DELF" ]
-        if (cpu_arch == "x64") {
+        if (current_cpu == "x64") {
           # TODO(ajwong): Why isn't this true in mac?
           yasm_flags += [ "-DPIC" ]
         }
       }
     }
   }
 }