Use a qualified path for grit/content_resources.h.

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" ]
 }
@@ skipping 20 matching lines @@
     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") {
@@ skipping 71 matching lines @@
     import("//build/config/crypto.gni")
     if (use_openssl) {
       defines += [ "WEBRTC_ANDROID_OPENSLEQS" ]
     }
   }
 
   if (is_posix) {
     defines += [ "WEBRTC_POSIX" ]
   }
 }