[Explore Sites] Adds the catalog proto.

This is used on the wire from the Explore Sites API to Chrome.

Bug: 867488
Change-Id: Id830f53b7ea7cfad8fbd6c7e38694d2de43ff558
Reviewed-on: https://chromium-review.googlesource.com/1210945Reviewed-by: Cathy Li <chili@chromium.org>
Commit-Queue: Justin DeWitt <dewittj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589535}

chrome/browser/BUILD.gn

@@ -2474,6 +2474,7 @@ jumbo_split_static_library("browser") {
     deps += [
       ":client_discourse_context_proto",
       ":delta_file_proto",
+      ":explore_sites_proto",
       ":jni_headers",
       "//chrome/browser/android/webapk:proto",
       "//chrome/services/media_gallery_util:manifest",  # TODO(xingliu): Tries to remove this.
@@ -4744,6 +4745,12 @@ if (is_android) {
       "android/proto/delta_file.proto",
     ]
   }
+
+  proto_library("explore_sites_proto") {
+    sources = [
+      "android/explore_sites/catalog.proto",
+    ]
+  }
 }
 
 if (is_win) {

chrome/browser/android/explore_sites/catalog.proto

+// Copyright 2018 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.
+
+syntax = "proto3";
+package explore_sites;
+
+option optimize_for = LITE_RUNTIME;
+
+// Represents the entire Explore Sites catalog, containing multiple categories
+// each with a list of sites.
+message Catalog {
+  // List of categories in priority order.  The first N will be shown directly
+  // on the NTP.
+  repeated Category categories = 1;
+}
+
+// A logical grouping of sites, with a title and an icon.
+message Category {
+  // The canonical types of category.
+  enum CategoryType {
+    DEFAULT = 0;
+    SOCIAL = 1;
+    ENTERTAINMENT = 2;
+    SPORT = 3;
+    NEWS = 4;
+    SHOPPING = 5;
+    REFERENCE = 6;
+    BANKING = 7;
+    GOVERNMENT = 8;
+    TRAVEL = 9;
+    EDUCATION = 10;
+    JOBS = 11;
+    APPS_GAMES = 12;
+    FAVORITE = 13;
+    GOOGLE = 14;
+    FOOD = 15;
+    HEALTH = 16;
+    BOOKS = 17;
+    TECHNOLOGY = 18;
+    SCIENCE = 19;
+  }
+
+  // Used to identify the category and as a hash tag within the Explore Sites
+  // page to scroll directly to this category.
+  CategoryType type = 1;
+
+  // Displayed beneath each title icon on the NTP as well as on the Explore
+  // Sites page. Localized to the primary language specified in the
+  // GetCatalogRequest.
+  string localized_title = 2;
+
+  // The icon that represents this category's sites.
+  // Binary encoding: WebP
+  // |icon| may be omitted for certain API requests.
+  bytes icon = 3;
+
+  // List of sites within the category in priority order.
+  // |sites| may be omitted for certain API requests.
+  repeated Site sites = 4;
+}
+
+// A single site that can be clicked on and navigated to from the Explore Sites
+// page.
+message Site {
+  // The url of the site that will be shown on click.
+  string site_url = 1;
+
+  // The icon of the site that can be displayed on the Explore Sites page.
+  // Binary encoding: WebP
+  bytes icon = 2;
+
+  // The title of the page that will be displayed near the page icon. This title
+  // will be in the language presented by the site, not localized to the user's
+  // language preferences.
+  string title = 3;
+}