Add chrome/browser/ui to the GN build.

build/config/features.gni

Index: build/config/features.gni
diff --git a/build/config/features.gni b/build/config/features.gni
index 07fd5a97692d63c978803454f64de3e55e9d0a9c..e6cbc0f88a05920947a373fbab5ad8f12ce9e6e5 100644
--- a/build/config/features.gni
+++ b/build/config/features.gni
@@ -23,6 +23,12 @@ declare_args() {
 
   # Enables Native Client support.
   enable_nacl = (!is_ios && !is_android)
+
+  # If debug_devtools is set to true, JavaScript files for DevTools are stored
+  # as is and loaded from disk. Otherwise, a concatenated file is stored in
+  # resources.pak. It is still possible to load JS files from disk by passing
+  # --debug-devtools cmdline switch.
+  debug_devtools = false
 }
 
 # Additional dependent variables -----------------------------------------------
@@ -144,3 +150,9 @@ enable_image_loader_extension = is_chromeos
 enable_remoting = !is_ios && !is_android
 
 enable_google_now = !is_ios && !is_android
+
+enable_one_click_signin = is_win || is_mac || (is_linux && !is_chromeos)
+
+# Chrome OS: whether to also build the upcoming version of
+# ChromeVox, which can then be enabled via a command-line switch.
+enable_chromevox_next = false