Uncouple the cros_custom_toolchain from chromeos.

build/config/BUILDCONFIG.gn

Index: build/config/BUILDCONFIG.gn
diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
index c91db167b34dcc8adcd98dab2e09835599b89727..6cf0b9edd04713220e6a02e963c8c677f5c4befb 100644
--- a/build/config/BUILDCONFIG.gn
+++ b/build/config/BUILDCONFIG.gn
@@ -145,12 +145,10 @@ declare_args() {
   # Compile for Thread Sanitizer to find threading bugs.
   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
-  }
+  # 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

[Dirk Pranke, 2015/08/13 20:25:16]

if this is no longer strictly tied to CrOS, should this just be called
'use_custom_toolchain', etc.?

 
   # DON'T ADD MORE FLAGS HERE. Read the comment above.
 }
@@ -587,7 +585,7 @@ if (is_win) {
     host_toolchain = "//build/toolchain/linux:$host_cpu"
     set_default_toolchain("//build/toolchain/linux:$current_cpu")
   }
-  if (is_chromeos && cros_use_custom_toolchain) {
+  if (cros_use_custom_toolchain) {
     set_default_toolchain("//build/toolchain/cros:target")
   }
 } else if (is_mac) {