Add chrome_sandbox as a data_dep of Chrome on ChromeOS.

You can't run the browser on a ChromeOS device without the
chrome_sandbox binary, so it makes sense for it to be a data_dep.
This is unnecessary for the "desktop ChromeOS" build, but
the binary isn't big so it's not much of an additional dependency.

R=rsesek@chromium.org

Change-Id: Ifd74b8ba2cc094d11686479d147d722661c21d10
Reviewed-on: https://chromium-review.googlesource.com/722239Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509583}

chrome/BUILD.gn

@@ -113,6 +113,9 @@ if (!is_android && !is_mac) {
     if (use_aura && (is_win || is_linux)) {
       data_deps += [ "//chrome/app:service_manifests" ]
     }
+    if (is_chromeos) {
+      data_deps += [ "//sandbox/linux:chrome_sandbox" ]
+    }
   }
 
   template("chrome_binary") {