deps: Roll cros_system_api dep to d7781180.

BUG=125176
TEST=builds
TBR=davemoore

Review URL: https://chromiumcodereview.appspot.com/10265009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@134532 0039d316-1c4b-4281-b951-d872f2087c98

tools/cros.DEPS/DEPS

@@ -7,6 +7,6 @@ deps_os = {
     "src/third_party/cros":
       Var("chromiumos_git") + "/platform/cros.git@377f51d8",
     "src/third_party/cros_system_api":
-      Var("chromiumos_git") + "/platform/system_api.git@b9812041",
+      Var("chromiumos_git") + "/platform/system_api.git@d7781180",
   }
 }