compose: Migrate empty_topic_placeholder to compose_state.

This makes it so that `drafts.js` now no longer imports `compose.js`.

web/src/compose.js

@@ -152,15 +152,11 @@ export function abort_video_callbacks(edit_message_id = "") {
     }
 }
 
-export function empty_topic_placeholder() {
-    return $t({defaultMessage: "(no topic)"});
-}
-
 export function create_message_object() {
     // Topics are optional, and we provide a placeholder if one isn't given.
     let topic = compose_state.topic();
     if (topic === "") {
-        topic = empty_topic_placeholder();
+        topic = compose_state.empty_topic_placeholder();
     }
 
     // Changes here must also be kept in sync with echo.try_deliver_locally

web/src/compose_state.js

@@ -2,6 +2,7 @@ import $ from "jquery";
 
 import * as compose_pm_pill from "./compose_pm_pill";
 import * as compose_recipient from "./compose_recipient";
+import {$t} from "./i18n";
 import * as sub_store from "./sub_store";
 
 let message_type = false; // 'stream', 'private', or false-y
@@ -100,6 +101,10 @@ export function set_compose_recipient_id(recipient_id) {
 // TODO: Break out setter and getter into their own functions.
 export const topic = get_or_set("stream_message_recipient_topic");
 
+export function empty_topic_placeholder() {
+    return $t({defaultMessage: "(no topic)"});
+}
+
 // We can't trim leading whitespace in `compose_textarea` because
 // of the indented syntax for multi-line code blocks.
 export const message_content = get_or_set("compose-textarea", true);

web/src/drafts.js

@@ -9,7 +9,6 @@ import render_draft_table_body from "../templates/draft_table_body.hbs";
 
 import * as blueslip from "./blueslip";
 import * as browser_history from "./browser_history";
-import * as compose from "./compose";
 import * as compose_actions from "./compose_actions";
 import * as compose_state from "./compose_state";
 import * as confirm_dialog from "./confirm_dialog";
@@ -347,7 +346,7 @@ export function format_draft(draft) {
             invite_only = sub.invite_only;
             is_web_public = sub.is_web_public;
         }
-        const draft_topic = draft.topic || compose.empty_topic_placeholder();
+        const draft_topic = draft.topic || compose_state.empty_topic_placeholder();
         const draft_stream_color = stream_data.get_color(draft.stream_id);
 
         formatted = {

web/src/message_edit.js

@@ -13,6 +13,7 @@ import * as channel from "./channel";
 import * as compose from "./compose";
 import * as compose_actions from "./compose_actions";
 import * as compose_banner from "./compose_banner";
+import * as compose_state from "./compose_state";
 import * as compose_ui from "./compose_ui";
 import * as compose_validate from "./compose_validate";
 import * as composebox_typeahead from "./composebox_typeahead";
@@ -756,7 +757,7 @@ export function start_inline_topic_edit($recipient_row) {
     const msg_id = rows.id_for_recipient_row($recipient_row);
     const message = message_lists.current.get(msg_id);
     let topic = message.topic;
-    if (topic === compose.empty_topic_placeholder()) {
+    if (topic === compose_state.empty_topic_placeholder()) {
         topic = "";
     }
     const $inline_topic_edit_input = $form.find(".inline_topic_edit");

web/src/message_list_view.js

@@ -11,8 +11,8 @@ import render_single_message from "../templates/single_message.hbs";
 
 import * as activity from "./activity";
 import * as blueslip from "./blueslip";
-import * as compose from "./compose";
 import * as compose_fade from "./compose_fade";
+import * as compose_state from "./compose_state";
 import * as condense from "./condense";
 import * as hash_util from "./hash_util";
 import {$t} from "./i18n";
@@ -176,7 +176,7 @@ function set_topic_edit_properties(group, message) {
 
     // Messages with no topics should always have an edit icon visible
     // to encourage updating them. Admins can also edit any topic.
-    if (message.topic === compose.empty_topic_placeholder()) {
+    if (message.topic === compose_state.empty_topic_placeholder()) {
         group.always_visible_topic_edit = true;
     } else {
         group.on_hover_topic_edit = true;

web/tests/popover_menus_data.test.js

@@ -11,7 +11,7 @@ const {MessageList} = zrequire("message_list");
 const message_lists = zrequire("message_lists");
 const popover_menus_data = zrequire("popover_menus_data");
 const people = zrequire("people");
-const compose = zrequire("compose");
+const compose_state = zrequire("compose_state");
 
 const noop = function () {};
 
@@ -242,7 +242,7 @@ test("not_my_message_view_source_and_move", () => {
             type: "stream",
             unread: false,
             collapsed: false,
-            topic: compose.empty_topic_placeholder(),
+            topic: compose_state.empty_topic_placeholder(),
             edit_history: [
                 {
                     prev_content: "Previous content",