Gate gtk on chromeos.

remoting/host/BUILD.gn

Index: remoting/host/BUILD.gn
diff --git a/remoting/host/BUILD.gn b/remoting/host/BUILD.gn
index 3605c8ebfac0f65cced714d54f8a938f83868f6d..57a1f599140ab5ba302740eca6aa17853ce06c57 100644
--- a/remoting/host/BUILD.gn
+++ b/remoting/host/BUILD.gn
@@ -90,7 +90,7 @@ if (is_mac) {  # TODO(GYP) Mac build of remoting host.
         "//build/config/linux:x11",
         "//build/config/linux:xrandr",
       ]
-      if (!is_chromeos) {
+      if (is_desktop_linux) {
         deps += [ "//build/config/linux/gtk2" ]
       }
     } else {
@@ -452,10 +452,10 @@ if (is_mac) {  # TODO(GYP) Mac build of remoting host.
         deps += [ "//third_party/libjingle:libjingle_webrtc" ]
       }
 
-      if (is_linux) {
+      if (is_desktop_linux) {
         deps += [ "//build/config/linux/gtk2" ]
       }
-      if (is_linux || is_mac) {
+      if ((is_linux && !is_chromeos) || is_mac) {
         libs = [ "pam" ]
       }
     }