Bug 1815864 - Use a bigger flex value in the tab box than the searchbar. r=dao

This prevents the searchbar from stealing all the free space from the
tab box.

Differential Revision: https://phabricator.services.mozilla.com/D169718

browser/base/content/browser.css

@@ -590,7 +590,7 @@ toolbar:not(#TabsToolbar) > #personal-bookmarks {
 #urlbar,
 #searchbar {
   /* Setting a width and min-width to let the location & search bars maintain
-     a constant width in case they haven't be resized manually. (bug 965772) */
+     a constant width in case they haven't been resized manually. (bug 965772) */
   width: 1px;
   min-width: 1px;
 }

browser/base/content/navigator-toolbox.inc.xhtml

@@ -53,7 +53,6 @@
 
           <tabs id="tabbrowser-tabs"
                 is="tabbrowser-tabs"
-                flex="1"
                 aria-multiselectable="true"
                 setfocus="false"
                 tooltip="tabbrowser-tab-tooltip"

browser/themes/shared/tabs.css

@@ -51,6 +51,9 @@
   --tab-loading-fill: #0A84FF;
   --tab-overflow-pinned-tabs-width: 0px;
   padding-inline: var(--tab-overflow-pinned-tabs-width) 0;
+  /* Use a bigger flex value than the searchbar to prevent it from
+   * taking all the toolbar space. */
+  -moz-box-flex: 1000;
 }
 
 #tabbrowser-tabpanels {