Implement BroadcastChannel

components/webmessaging/BUILD.gn

Index: components/webmessaging/BUILD.gn
diff --git a/services/user/public/interfaces/BUILD.gn b/components/webmessaging/BUILD.gn
similarity index 52%
copy from services/user/public/interfaces/BUILD.gn
copy to components/webmessaging/BUILD.gn
index 0f2415baa1dae16c6169579b47e3dc5a031e0807..e7330827b0a219cdb4c3c1f5c6ccd331f90cd3e2 100644
--- a/services/user/public/interfaces/BUILD.gn
+++ b/components/webmessaging/BUILD.gn
@@ -4,12 +4,22 @@
 
 import("//mojo/public/tools/bindings/mojom.gni")
 
+mojom_files = [ "broadcast_channel.mojom" ]
+
 mojom("interfaces") {
+  sources = mojom_files
+}
+
+static_library("webmessaging") {
   sources = [
-    "user_service.mojom",
+    "broadcast_channel_service.cc",
+    "broadcast_channel_service.h",
   ]
 
   deps = [
-    "//components/filesystem/public/interfaces",
+    ":interfaces",
+    "//base",
+    "//mojo/common",
+    "//url",
   ]
 }