Add //chrome/browser/ui to "gn check".

.gn

 # This file is used by the GN meta build system to find the root of the source
 # tree and to set startup options. For documentation on the values set in this
 # file, run "gn help dotfile" at the command line.
 
 # The location of the build configuration file.
 buildconfig = "//build/config/BUILDCONFIG.gn"
 
 # The secondary source root is a parallel directory tree where
 # GN build files are placed when they can not be placed directly
 # in the source tree, e.g. for third party source trees.
@@ skipping 10 matching lines @@
   "//blimp/*",
   "//blink/*",
   "//breakpad/*",
   "//build/*",
   "//cc/*",
 
   #"//chrome/*",  # Epic number of errors.
   "//chrome/app/*",
   "//chrome/browser/extensions/*",
 
-  #"//chrome/browser/ui/*",  # Just a few things left
+  "//chrome/browser/ui/*",
   "//chrome/common/*",
   "//chrome/installer/*",
   "//chrome/third_party/mozilla_security_manager/*",
   "//chrome/tools/*",
   "//chrome/utility/*",
   "//chromecast/*",
   "//chromeos/*",
   "//chrome_elf/*",
   "//cloud_print/*",
   "//components/*",
@@ skipping 215 matching lines @@
   "//third_party/google_input_tools/inputview.gni",
   "//third_party/skia/gn/shared_sources.gni",
 
   # CLD2 should be removed soon, delete this when we do.
   "//third_party/cld_2/BUILD.gn",
 
   # Not gypi-to-gn.
   "//google_apis/BUILD.gn",
   "//printing/BUILD.gn",
 ]