Roll GN binaries to #317120 for the cpu_arch changes

build/config/BUILDCONFIG.gn

 # Copyright (c) 2013 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.
 
 # =============================================================================
 # BUILD FLAGS
 # =============================================================================
 #
 # This block lists input arguments to the build, along with their default
 # values. GN requires listing them explicitly so it can validate input and have
 # a central place to manage the build flags.
 #
 # If a value is specified on the command line, it will overwrite the defaults
 # given here, otherwise the default will be injected into the root scope.
 #
 # KEEP IN ALPHABETICAL ORDER and write a good description for everything.
 # Use "is_*" names for intrinsic platform descriptions and build modes, and
 # "use_*" names for optional features libraries, and configurations.
+
+# TODO(dpranke): The os and cpu_arch variables exist for backwards
+# compatibility and should be deleted once all of the build files and
+# bots have been updated to use current_cpu/target_cpu and
+# current_os/target_os instead.
+
+if (target_os == "") {
+  if (defined(os)) {
+    # If os is defined, it was set in an args file and needs to be
+    # used for backwards-compatibility.
+    target_os = os
+  } else {
+    target_os = host_os
+  }
+}
+
+if (target_cpu == "") {
+  if (defined(cpu_arch)) {
+    # If cpu_arch is defined, it was set in an args file and needs to be
+    # used for backwards-compatibility.
+    target_cpu = cpu_arch
+  } else {
+    target_cpu = host_cpu
+  }
+}
+
+if (current_cpu == "") {
+  current_cpu = target_cpu
+}
+if (current_os == "") {
+  current_os = target_os
+}
+
 declare_args() {
+  # TODO(dpranke): These values are here for backwards compatibility and
+  # should be deleted when all of the builders and configs have been updated.
+  cpu_arch = target_cpu
+  os = target_os
+  build_cpu_arch = host_cpu
+  build_os = host_os
+
   # How many symbols to include in the build. This affects the performance of
   # the build since the symbols are large and dealing with them is slow.
   #   2 means regular build with symbols.
   #   1 means minimal symbols, usually enough for backtraces only.
   #   0 means no symbols.
   #   -1 means auto-set (off in release, regular in debug).
   symbol_level = -1
 
   # Component build.
   is_component_build = false
@@ skipping 46 matching lines @@
   # cross-compiles (compiling the same target for multiple toolchains in the
   # same build) to work.
   target_arch = "arm"
 
   # TODO(brettw) remove this flag (and therefore enable linking all targets) on
   # Windows when we have sufficient bot capacity. In the meantime, you can
   # enable linking for local compiles.
   link_chrome_on_windows = true
 }
 
+# TODO(dpranke): Remove these asserts when os and cpu_arch are removed.
+assert(current_cpu == cpu_arch)
+assert(current_os == os)
+
 # =============================================================================
 # OS DEFINITIONS
 # =============================================================================
 #
 # We set these various is_FOO booleans for convenience in writing OS-based
 # conditions.
 #
 # - is_android, is_chromeos, is_ios, and is_win should be obvious.
 # - is_mac is set only for desktop Mac. It is not set on iOS.
 # - is_posix is true for mac and any Unix-like system (basically everything
@@ skipping 624 matching lines @@
       }
       if (defined(invoker.testonly)) {
         testonly = invoker.testonly
       }
       if (defined(invoker.visibility)) {
         visibility = invoker.visibility
       }
     }
   }
 }