[fuchsia] Add UrlRequestRewriteRulesProvider cast API.

Bug: 976975
Change-Id: Ia14d5475b94f4fb2579dfddfa54a544157f8e3ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1761235
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689577}

fuchsia/BUILD.gn

@@ -14,6 +14,7 @@ fidl_library("cast_fidl") {
     "fidl/cast/api_bindings.fidl",
     "fidl/cast/application_config.fidl",
     "fidl/cast/application_controller.fidl",
+    "fidl/cast/url_request_rewriter.fidl",
   ]
 
   public_deps = [

fuchsia/fidl/cast/url_request_rewriter.fidl

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+library chromium.cast;
+
+using fuchsia.web;
+
+/// Provides URL request rewriting rules from the Agent.
+[Discoverable]
+protocol UrlRequestRewriteRulesProvider {
+    /// Returns a set of URL request rewriting rules. The first call must always
+    /// return immediately with a potentially empty set of rules. On subsequent
+    /// calls, the callback will only be invoked when the rules have changed.
+    GetUrlRequestRewriteRules() ->
+        (vector<fuchsia.web.UrlRequestRewriteRule> rules);
+};