Implement browser-side host resolver Mojo service.

net/BUILD.gn

Index: net/BUILD.gn
diff --git a/net/BUILD.gn b/net/BUILD.gn
index 52444d59ea4a765dbf23711ab50d232593c8079f..a567f2cf09631e09c1de364d01128e5feba74785 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -790,6 +790,35 @@ if (use_v8_in_net) {
   }
 }
 
+if (use_v8_in_net && !is_android) {
+  static_library("net_browser_services") {
+    sources = [
+      "dns/mojo_host_resolver_impl.cc",
+      "dns/mojo_host_resolver_impl.h",
+    ]
+
+    public_deps = [
+      ":net",
+      ":type_converters",
+      "//net/interfaces",
+      "//third_party/mojo/src/mojo/public/cpp/bindings",
+    ]
+  }
+
+  static_library("type_converters") {
+    sources = [
+      "dns/type_converters.cc",
+      "dns/type_converters.h",
+    ]
+
+    public_deps = [
+      ":net",
+      "//net/interfaces",
+      "//third_party/mojo/src/mojo/public/cpp/bindings",
+    ]
+  }
+}
+
 if (!is_ios && !is_android) {
   executable("crash_cache") {
     testonly = true
@@ -1319,6 +1348,16 @@ if (!is_android && !is_win && !is_mac) {
       ]
     }
 
+    if (use_v8_in_net && !is_android) {
+      deps += [
+        ":net_browser_services",
+        "//mojo/environment:chromium",
+        "//third_party/mojo/src/mojo/edk/system",
+      ]
+    } else {
+      sources -= [ "dns/mojo_host_resolver_impl_unittest.cc" ]
+    }
+
     if (!enable_mdns) {
       sources -= [
         "dns/mdns_cache_unittest.cc",