drafts: Change foreground for dark background streams in drafts modal.

In drafts modal, dark background streams still had black foreground;
This changes the foreground to white for the same.

frontend_tests/node_tests/drafts.js

@@ -7,6 +7,8 @@ zrequire('XDate', 'xdate');
 zrequire('timerender');
 zrequire('Handlebars', 'handlebars');
 zrequire('util');
+zrequire('stream_color');
+zrequire('colorspace');
 
 var ls_container = {};
 var noop = function () { return; };
@@ -261,6 +263,7 @@ run_test('format_drafts', () => {
             is_stream: true,
             stream: 'stream',
             stream_color: '#FFFFFF',
+            dark_background: '',
             topic: 'topic',
             raw_content: 'Test Stream Message',
             time_stamp: '7:55 AM',
@@ -291,6 +294,7 @@ run_test('format_drafts', () => {
             is_stream: true,
             stream: 'stream 2',
             stream_color: '#FFFFFF',
+            dark_background: '',
             topic: 'topic',
             raw_content: 'Test Stream Message 2',
             time_stamp: 'Jan 21',

static/js/drafts.js

@@ -212,6 +212,7 @@ exports.format_draft = function (draft) {
         var space_string = new Handlebars.SafeString(" ");
         var stream = draft.stream.length > 0 ? draft.stream : space_string;
         var draft_topic = util.get_draft_topic(draft);
+        var draft_stream_color = stream_data.get_color(draft.stream);
 
         if (draft_topic === '') {
             draft_topic = compose.empty_topic_placeholder();
@@ -221,7 +222,8 @@ exports.format_draft = function (draft) {
             draft_id: draft.id,
             is_stream: true,
             stream: stream,
-            stream_color: stream_data.get_color(draft.stream),
+            stream_color: draft_stream_color,
+            dark_background: stream_color.get_color_class(draft_stream_color),
             topic: draft_topic,
             raw_content: draft.content,
             time_stamp: time_stamp,

static/templates/draft.handlebars

@@ -3,7 +3,7 @@
         {{#if is_stream}}
         <div class="message_header message_header_stream">
             <div class="message-header-contents">
-                <div class="message_label_clickable stream_label"
+                <div class="message_label_clickable stream_label {{dark_background}}"
                   style="background: {{stream_color}}; border-left-color: {{stream_color}};">
                     {{stream}}
                 </div>