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

third_party/boringssl/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.
 
 # Config for us and everybody else depending on BoringSSL.
 config("openssl_config") {
   include_dirs = []
   include_dirs += [ "src/include" ]
   if (is_component_build) {
     defines = [ "BORINGSSL_SHARED_LIBRARY" ]
@@ skipping 10 matching lines @@
     exec_script("//build/gypi_to_gn.py",
                 [ rebase_path("//third_party/boringssl/boringssl.gypi") ],
                 "scope",
                 [ "//third_party/boringssl/boringssl.gypi" ])
 
 # Windows' assembly is built with Yasm. The other platforms use the platform
 # assembler.
 if (is_win) {
   import("//third_party/yasm/yasm_assemble.gni")
   yasm_assemble("boringssl_asm") {
-    if (cpu_arch == "x64") {
+    if (current_cpu == "x64") {
       sources = gypi_values.boringssl_win_x86_64_sources
-    } else if (cpu_arch == "x86") {
+    } else if (current_cpu == "x86") {
       sources = gypi_values.boringssl_win_x86_sources
     }
   }
 }
 
 component("boringssl") {
   sources = gypi_values.boringssl_lib_sources
 
   public_configs = [ ":openssl_config" ]
 
@@ skipping 19 matching lines @@
     # cannot use relative paths to find this file.
     "src/crypto",
   ]
 
   if (is_win) {
     # TODO(davidben): Fix size_t truncations in BoringSSL.
     # https://crbug.com/429039
     cflags += [ "/wd4267" ]
   }
 
-  if (cpu_arch == "x64") {
+  if (current_cpu == "x64") {
     if (is_mac) {
       sources += gypi_values.boringssl_mac_x86_64_sources
     } else if (is_linux || is_android) {
       sources += gypi_values.boringssl_linux_x86_64_sources
     } else if (is_win) {
       deps += [ ":boringssl_asm" ]
     } else {
       defines += [ "OPENSSL_NO_ASM" ]
     }
-  } else if (cpu_arch == "x86") {
+  } else if (current_cpu == "x86") {
     if (is_mac) {
       sources += gypi_values.boringssl_mac_x86_sources
     } else if (is_linux || is_android) {
       sources += gypi_values.boringssl_linux_x86_sources
     } else if (is_win) {
       deps += [ ":boringssl_asm" ]
     } else {
       defines += [ "OPENSSL_NO_ASM" ]
     }
-  } else if (cpu_arch == "arm") {
+  } else if (current_cpu == "arm") {
     sources += gypi_values.boringssl_linux_arm_sources
-  } else if (cpu_arch == "arm64") {
+  } else if (current_cpu == "arm64") {
     sources += gypi_values.boringssl_linux_aarch64_sources
   } else {
     defines += [ "OPENSSL_NO_ASM" ]
   }
 }