feat: add functionality to allow pinned tabs to resemble normal tabs

(cherry picked from commit 9c79b7c01b6acb6f3c4ae187353e7131d8ef0a34)

waterfox/browser/app/profile/000-waterfox.js

@@ -64,6 +64,7 @@ pref("browser.ping-centre.telemetry", false, locked);
 pref("browser.search.separatePrivateDefault", true);
 pref("browser.search.separatePrivateDefault.ui.enabled", true);
 pref("browser.send_pings", false, locked);
+pref("browser.tabs.pinnedIconOnly", false);
 pref("browser.tabs.remote.separatedMozillaDomains", "", locked);
 pref("browser.topsites.contile.enabled", false, locked);
 pref("browser.topsites.contile.endpoint", "", locked);

waterfox/browser/components/WaterfoxGlue.jsm

@@ -72,6 +72,16 @@ const WaterfoxGlue = {
         }
       }
     );
+
+    // Keep the pinned tabs observer
+    this.pinnedTabListener = PrefUtils.addObserver(
+      "browser.tabs.pinnedIconOnly",
+      isEnabled => {
+        // Pref being true actually means we need to unload the sheet, so invert.
+        const uri = "chrome://browser/content/tabfeatures/pinnedtab.css";
+        BrowserUtils.registerOrUnregisterSheet(uri, !isEnabled);
+      }
+    );
   },
 
   async getChromeManifest(manifest) {

waterfox/browser/components/tabfeatures/content/pinnedtab.css

@@ -0,0 +1,24 @@
+@supports not -moz-bool-pref("browser.tabs.pinnedIconOnly") {
+  .tabbrowser-tab:is([pinned]) {
+    -moz-box-flex: 100;
+    max-width: 225px;
+    min-width: var(--tab-min-width);
+    width: 0;
+    transition: min-width 100ms ease-out,
+                max-width 100ms ease-out;
+  }
+
+  .tabbrowser-tab:is([pinned]):not([fadein]) {
+    max-width: 0.1px;
+    min-width: 0.1px;
+    visibility: hidden;
+  }
+
+  .tabbrowser-tab:is([pinned]) .tab-throbber,
+  .tabbrowser-tab:is([pinned]) .tab-icon-pending,
+  .tabbrowser-tab:is([pinned]) .tab-icon-image,
+  .tabbrowser-tab:is([pinned]) .tab-sharing-icon-overlay,
+  .tabbrowser-tab:is([pinned]) .tab-icon-overlay {
+    margin-inline-end: 5.5px;
+  }
+}

waterfox/browser/components/tabfeatures/jar.mn

@@ -1,3 +1,4 @@
 browser.jar:
 %  content browser %content/browser/ contentaccessible=yes
 *    content/browser/overlays/tabfeatures.xhtml            (content/tabfeatures.xhtml)
+     content/browser/tabfeatures/pinnedtab.css             (content/pinnedtab.css)