Fix pkg-config issue with cras for Chrome OS build.

media/audio/BUILD.gn

Index: media/audio/BUILD.gn
diff --git a/media/audio/BUILD.gn b/media/audio/BUILD.gn
index 48f1453b92092de28f73adf9cc8b343d87ecda39..3ea1666e26a58a0f4d50b4f9ace8c95af366d992 100644
--- a/media/audio/BUILD.gn
+++ b/media/audio/BUILD.gn
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/linux/pkg_config.gni")
 import("//media/media_options.gni")
 
 # When libpulse is not directly linked, use stubs to allow for dlopening of the
@@ -207,7 +208,7 @@ source_set("audio") {
     pkg_config("libcras") {
       packages = [ "libcras" ]
     }
-    configs += [ "libcras" ]
+    configs += [ ":libcras" ]
   }
 
   if (use_pulseaudio) {