Pull GN @ 252040, update calls

build/config/sysroot.gni

Index: build/config/sysroot.gni
diff --git a/build/config/sysroot.gni b/build/config/sysroot.gni
index 6340c3a7d197792cb65772af998b9bdffff6491f..cecc1eabfeb2c61bd6eede44f9575fa4b9fb8e61 100644
--- a/build/config/sysroot.gni
+++ b/build/config/sysroot.gni
@@ -24,18 +24,17 @@ if (is_android) {
   # For official builds, use the sysroot checked into the internal source repo
   # so that the builds work on older versions of Linux.
   if (cpu_arch == "x64") {
-    sysroot = rebase_path(
-      "//chrome/installer/linux/debian_wheezy_amd64-sysroot", ".", "")
+    sysroot =
+        rebase_path("//chrome/installer/linux/debian_wheezy_amd64-sysroot")
   } else if (cpu_arch == "x86") {
-    sysroot = rebase_path(
-      "//chrome/installer/linux/debian_wheezy_i386-sysroot", ".", "")
+    sysroot = rebase_path("//chrome/installer/linux/debian_wheezy_i386-sysroot")
   } else {
     # Any other builds don't use a sysroot.
     sysroot = ""
   }
 } else if (is_linux && !is_chromeos) {
   if (cpu_arch == "mipsel") {
-    sysroot = rebase_path("//mipsel-sysroot/sysroot", ".", "")
+    sysroot = rebase_path("//mipsel-sysroot/sysroot")
   } else {
     sysroot = ""
   }