icecc support for cros host build

build/toolchain/cros/BUILD.gn

Index: build/toolchain/cros/BUILD.gn
diff --git a/build/toolchain/cros/BUILD.gn b/build/toolchain/cros/BUILD.gn
index bf139dc12da8192f02bd1e7c83e18c3a77f795a5..f9331b870e969160b0c21e643da126587e08ba7d 100644
--- a/build/toolchain/cros/BUILD.gn
+++ b/build/toolchain/cros/BUILD.gn
@@ -22,6 +22,9 @@ gcc_toolchain("target") {
   if (cros_target_readelf != "") {
     readelf = cros_target_readelf
   }
+  if (cc_wrapper != "") {
+    print("cc_wrapper is not supported on target build. crbug.com/645435")
+  }
   extra_cflags = cros_target_extra_cflags
   extra_cppflags = cros_target_extra_cppflags
   extra_cxxflags = cros_target_extra_cxxflags
@@ -73,10 +76,16 @@ gcc_toolchain("nacl_bootstrap") {
 }
 
 gcc_toolchain("host") {
+  if (cc_wrapper != "") {
+    compiler_prefix = cc_wrapper + " "
+  } else {
+    compiler_prefix = ""
+  }
+
   # These are args for the template.
   ar = cros_host_ar
-  cc = cros_host_cc
-  cxx = cros_host_cxx
+  cc = compiler_prefix + cros_host_cc
+  cxx = compiler_prefix + cros_host_cxx
   ld = cxx
   if (cros_host_ld != "") {
     ld = cros_host_ld