Adds simple browser-side implementation for DNS prefetching.

components/dns_prefetch/browser/BUILD.gn

Index: components/dns_prefetch/browser/BUILD.gn
diff --git a/components/cdm/browser/BUILD.gn b/components/dns_prefetch/browser/BUILD.gn
similarity index 58%
copy from components/cdm/browser/BUILD.gn
copy to components/dns_prefetch/browser/BUILD.gn
index e18b67035e55756ee7f08d3048949c8f8a7feb7b..f6cdd8304a32e2bee99bd7bc2b5c7ee9fb6453d7 100644
--- a/components/cdm/browser/BUILD.gn
+++ b/components/dns_prefetch/browser/BUILD.gn
@@ -2,17 +2,15 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# GYP version: components/dns_prefetch.gypi:dns_prefetch_browser
 source_set("browser") {
   sources = [
-    "cdm_message_filter_android.cc",
-    "cdm_message_filter_android.h",
+    "net_message_filter.cc",
+    "net_message_filter.h",
   ]
 
-  deps = [
-    "//base",
-    "//components/cdm/common",
+  public_deps = [
     "//content/public/browser",
-    "//content/public/common",
-    "//media",
+    "//net",
   ]
 }