Decompose //extensions/browser/BUILD.gn

extensions/browser/api/dns/BUILD.gn

Index: extensions/browser/api/dns/BUILD.gn
diff --git a/components/leveldb/public/interfaces/BUILD.gn b/extensions/browser/api/dns/BUILD.gn
similarity index 57%
copy from components/leveldb/public/interfaces/BUILD.gn
copy to extensions/browser/api/dns/BUILD.gn
index 0b95cf4b365afc2bf68220e01f2eca7ac41d5b35..452e716a5d4579b03a8cffd9ce6ed0b8a8d983ec 100644
--- a/components/leveldb/public/interfaces/BUILD.gn
+++ b/extensions/browser/api/dns/BUILD.gn
@@ -2,14 +2,15 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//mojo/public/tools/bindings/mojom.gni")
-
-mojom("interfaces") {
+source_set("dns") {
   sources = [
-    "leveldb.mojom",
+    "dns_api.cc",
+    "dns_api.h",
+    "host_resolver_wrapper.cc",
+    "host_resolver_wrapper.h",
   ]
 
   deps = [
-    "//components/filesystem/public/interfaces",
+    "//extensions/common/api",
   ]
 }