Introduce dart_host_toolchain arg, remove '--checked' option from patch_sdk.py

utils/generate_patch_sdk.gni

Index: utils/generate_patch_sdk.gni
diff --git a/utils/generate_patch_sdk.gni b/utils/generate_patch_sdk.gni
index 4ec995784dd982469c7308f03bbbecee89a65228..127ed91c7f9a5a1284507b4a7bdbb8415c077053 100644
--- a/utils/generate_patch_sdk.gni
+++ b/utils/generate_patch_sdk.gni
@@ -6,6 +6,10 @@ import("../build/prebuilt_dart_sdk.gni")
 
 _dart_root = get_path_info("..", "abspath")
 
+declare_args() {
+  dart_host_toolchain = host_toolchain

[rmacnak, 2017/06/21 21:15:34]

Can we use this for the standalone's invocation of gen_snapshot($host_toolchain)
as well? See also use of host_toolchain in compiled_action.gni

[aam, 2017/06/21 21:39:18]

Do you mean invocation in flutter/build/flutter_app.gni? Sure if that's make
sense.
Does that have to be switched to use of dart_host_toolchain too?

[aam, 2017/06/22 04:34:07]

Done.

+}
+
 # Template to generate a patched_sdk folder. This invokes the tools/patch_sdk.py
 # script and sets up the right dependencies.
 #
@@ -28,7 +32,7 @@ template("generate_patched_sdk") {
     }
 
     if (!prebuilt_dart_exe_works) {
-      deps += [ "$_dart_root/runtime/bin:dart_bootstrap_host_arch($host_toolchain)" ]
+      deps += [ "$_dart_root/runtime/bin:dart_bootstrap_host_arch($dart_host_toolchain)" ]
     }
 
     script = "$_dart_root/tools/patch_sdk.py"
@@ -49,7 +53,7 @@ template("generate_patched_sdk") {
     args = [ "--quiet" ]
     if (!prebuilt_dart_exe_works) {
       dart_out_dir = get_label_info(
-              "$_dart_root/runtime/bin:dart_bootstrap_host_arch($host_toolchain)",
+              "$_dart_root/runtime/bin:dart_bootstrap_host_arch($dart_host_toolchain)",
               "root_out_dir")
       dart_bootstrap = rebase_path(
               "$dart_out_dir/dart_bootstrap_host_arch$executable_suffix")