Provide a way to disable libpci dependency.

gpu/config/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("//build/config/ui.gni")
 
 source_set("config") {
   sources = [
     "dx_diag_node.cc",
     "dx_diag_node.h",
@@ skipping 44 matching lines @@
     deps += [ "//third_party/libxml" ]
     libs = [ "dxguid.lib", "setupapi.lib" ]
 
     if (is_chrome_branded && is_official_build) {
       sources += [
         "//third_party/amd/AmdCfxPxExt.h",
         "//third_party/amd/amd_videocard_info_win.cc",
       ]
     }
   }
-  if (is_linux && (use_x11 || use_ozone)) {
+  if(use_libpci) {

[brettw, 2014/10/30 17:00:50]

space before (

+    defines += [ "USE_LIBPCI=1" ]
+  }
+  if (is_linux && use_libpci && (use_x11 || use_ozone)) {
     deps += [
       "//build/config/linux:libpci",
     ]
   }
   if (is_linux && use_x11) {
     configs += [
       "//build/config/linux:x11",
       "//build/config/linux:xext",
     ]
     deps += [
       "//third_party/libXNVCtrl",
     ]
   } else {
     sources -= [ "gpu_info_collector_x11.cc" ]
   }
   if (!use_ozone) {
     sources -= [ "gpu_info_collector_ozone.cc" ]
   }
 }