Make ui gn check pass. Misc GN build improvements.

content/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//tools/grit/grit_rule.gni")
 
 # Applied by targets internal to content.
 config("content_implementation") {
   defines = [ "CONTENT_IMPLEMENTATION" ]
 }
 
 content_shared_components = [
   "//content/gpu",
   "//content/plugin",
   "//content/ppapi_plugin",
-  "//content/public/app",
   "//content/public/browser:sources",
   "//content/public/child",
   "//content/public/common",
   "//content/public/plugin",
   "//content/public/renderer",
   "//content/renderer",
   "//content/utility",
 ]
 
 if (is_component_build) {
   shared_library("content") {
     deps = content_shared_components + [
       "//content/app",
+      "//content/public/app",
     ]
     forward_dependent_configs_from = deps
   }
 } else {
   group("content") {
     deps = content_shared_components
   }
 }
 
 grit("resources") {
   source = "content_resources.grd"
   use_qualified_include = true
   outputs = [
     "grit/content_resources.h",
     "content_resources.pak",
     "content_resources.rc",
   ]
 }
 
 # This target exists to "hold" the content_export header so we can do proper
 # inclusion testing of it.
 source_set("export") {
   visibility = "//content/*"
   sources = [
     "content/common/content_export.h"
   ]
 }