media: Support MojoMediaApplication in GPU process.

content/browser/BUILD.gn

Index: content/browser/BUILD.gn
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index 9160cc7cf47cb3a8f8a5b98dde91965f200c491d..5d9e588933e47cbab845f1cfec3cfb3e6ce30ee8 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -485,6 +485,10 @@ source_set("browser") {
     deps += [ "//third_party/boringssl" ]
   }
 
+  if (enable_mojo_media != "none") {
+    configs += [ "//media/mojo/services:enable_mojo_media_config" ]
+  }
+
   if (enable_mojo_media == "browser") {
     deps += [ "//media/mojo/services:application" ]
   }