Remove old references to cpu_arch, os from GN files.

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
-  }
+  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 if (target_os == "android") {
+  if (target_os == "android") {
     # If we're building for Android, we should assume that we want to
     # build for ARM by default, not the host_cpu (which is likely x64).
     # This allows us to not have to specify both target_os and target_cpu
     # on the command line.
     target_cpu = "arm"
   } 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 32 matching lines @@
   is_tsan = false
 
   if (current_os == "chromeos") {
     # Allows the target toolchain to be injected as arguments. This is needed
     # to support the CrOS build system which supports per-build-configuration
     # toolchains.
     cros_use_custom_toolchain = false
   }
 }
 
-# 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 400 matching lines @@
   }
 } else if (is_mac) {
   host_toolchain = "//build/toolchain/mac:clang"
   set_default_toolchain(host_toolchain)
 } else if (is_ios) {
   host_toolchain = "//build/toolchain/mac:host_clang"
   set_default_toolchain("//build/toolchain/mac:clang")
 } else if (is_nacl) {
   # TODO(GYP): This will need to change when we get NaCl working
   # on multiple platforms, but this whole block of code (how we define
-  # host_toolchain) needs to be reworked regardless to key off of build_os
-  # and build_cpu_arch rather than the is_* variables.
+  # host_toolchain) needs to be reworked regardless to key off of host_os
+  # and host_cpu rather than the is_* variables.
   host_toolchain = "//build/toolchain/linux:clang_x64"
 }
 
 # ==============================================================================
 # COMPONENT SETUP
 # ==============================================================================
 
 # TODO(brettw) erase this once the built-in "component" function is removed.
 if (is_component_build) {
   component_mode = "shared_library"
@@ skipping 190 matching lines @@
       }
       if (defined(invoker.testonly)) {
         testonly = invoker.testonly
       }
       if (defined(invoker.visibility)) {
         visibility = invoker.visibility
       }
     }
   }
 }