Bug 1728458 - Migrate browser-box.inc.xhtml to Fluent. r=emalysz,fluent-reviewers,flod

Differential Revision: https://phabricator.services.mozilla.com/D124384

browser/base/content/browser-box.inc.xhtml

@@ -16,7 +16,7 @@
 # To ensure the button doesn't expand unnecessarily for short labels, the
 # spacer should significantly out-flex the button.
       <spacer flex="1000"/>
-      <toolbarbutton id="sidebar-close" class="close-icon tabbable" tooltiptext="&sidebarCloseButton.tooltip;" oncommand="SidebarUI.hide();"/>
+      <toolbarbutton id="sidebar-close" class="close-icon tabbable" data-l10n-id="sidebar-close-button" oncommand="SidebarUI.hide();"/>
     </box>
     <browser id="sidebar" flex="1" autoscroll="false" disablehistory="true" disablefullscreen="true"
               style="min-width: 14em; width: 18em; max-width: 36em;" tooltip="aHTMLTooltip"/>

browser/locales/en-US/browser/sidebarMenu.ftl

@@ -13,3 +13,6 @@ sidebar-menu-synced-tabs =
 
 sidebar-menu-close =
   .label = Close Sidebar
+
+sidebar-close-button =
+  .tooltiptext = Close sidebar

browser/locales/en-US/chrome/browser/browser.dtd

@@ -62,8 +62,6 @@ this container is a toolbar. This avoids double-speaking. -->
 
 <!ENTITY fullZoom.label                 "Zoom">
 
-<!ENTITY sidebarCloseButton.tooltip     "Close sidebar">
-
 <!-- Name for the tabs toolbar as spoken by screen readers.
      The word "toolbar" is appended automatically and should not be contained below! -->
 <!ENTITY tabsToolbar.label "Browser tabs">

python/l10n/fluent_migrations/bug_1728458_migrate_browser_box.py

@@ -0,0 +1,26 @@
+# coding=utf8
+
+# Any copyright is dedicated to the Public Domain.
+# http://creativecommons.org/publicdomain/zero/1.0/
+
+from __future__ import absolute_import
+import fluent.syntax.ast as FTL
+from fluent.migrate.helpers import transforms_from, VARIABLE_REFERENCE
+from fluent.migrate import REPLACE, COPY
+
+
+def migrate(ctx):
+    """Bug 1728458 - Migrate browser-box.inc.xhtml to Fluent, part {index}"""
+    target = "browser/browser/sidebarMenu.ftl"
+    reference = "browser/browser/sidebarMenu.ftl"
+    ctx.add_transforms(
+        target,
+        reference,
+        transforms_from(
+            """
+sidebar-close-button =
+    .tooltiptext = { COPY(from_path, "sidebarCloseButton.tooltip") }
+""",
+            from_path="browser/chrome/browser/browser.dtd",
+        ),
+    )