Decompose //extensions/browser/BUILD.gn

extensions/browser/api/messaging/BUILD.gn

Index: extensions/browser/api/messaging/BUILD.gn
diff --git a/components/leveldb/public/interfaces/BUILD.gn b/extensions/browser/api/messaging/BUILD.gn
similarity index 57%
copy from components/leveldb/public/interfaces/BUILD.gn
copy to extensions/browser/api/messaging/BUILD.gn
index 0b95cf4b365afc2bf68220e01f2eca7ac41d5b35..a2f6bd18510baf622ae244f16eec94c5a65db6e1 100644
--- a/components/leveldb/public/interfaces/BUILD.gn
+++ b/extensions/browser/api/messaging/BUILD.gn
@@ -2,14 +2,14 @@
 # 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("messaging") {
   sources = [
-    "leveldb.mojom",
+    "native_message_host.cc",
+    "native_message_host.h",
+    "native_messaging_channel.h",
   ]
 
   deps = [
-    "//components/filesystem/public/interfaces",
+    "//extensions/common/api",
   ]
 }