Use clang for snapshot_toolchain by default, except on ChromeOS.

snapshot_toolchain.gni

Index: snapshot_toolchain.gni
diff --git a/snapshot_toolchain.gni b/snapshot_toolchain.gni
index a03e35a26ebbc8c9c4f769f65ab26bbf9abad801..1f652229a020fa86542338e89d6abb158cde5196 100644
--- a/snapshot_toolchain.gni
+++ b/snapshot_toolchain.gni
@@ -25,6 +25,7 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+import("//build/config/chromecast_build.gni")

[jochen (gone - plz use gerrit), 2016/08/22 15:46:53]

why is that required here?

[slan, 2016/08/22 15:54:25]

is_chromecast is declared in that file. 

[jochen (gone - plz use gerrit), 2016/08/22 15:57:46]

but we also don't include special files to get the definition of is_android

 import("//build/config/v8_target_cpu.gni")
 
 declare_args() {
@@ -72,7 +73,7 @@ if (v8_snapshot_toolchain == "") {
     # cpu or a different target OS. Assume the same toolchain (Clang or GCC
     # or MSVS) for target and host, unless this is an Android build, where
     # Clang is always used on the host.
-    if (is_clang || is_android) {
+    if (is_clang || is_android || is_chromecast) {
       _clang = "clang_"
     } else {
       _clang = ""