Bug 1625464 - Invert the logic of the `notoverflowing` attribute. r=ntim

Differential Revision: https://phabricator.services.mozilla.com/D68563

--HG--
extra : moz-landing-system : lando

browser/base/content/test/tabs/browser_newwindow_tabstrip_overflow.js

@@ -24,7 +24,7 @@ add_task(async function withoutLWT() {
     "tab container not overflowing"
   );
   ok(
-    win.gBrowser.tabContainer.arrowScrollbox.hasAttribute("notoverflowing"),
+    !win.gBrowser.tabContainer.arrowScrollbox.hasAttribute("overflowing"),
     "arrow scrollbox not overflowing"
   );
   await BrowserTestUtils.closeWindow(win);
@@ -38,7 +38,7 @@ add_task(async function withLWT() {
     "tab container not overflowing"
   );
   ok(
-    win.gBrowser.tabContainer.arrowScrollbox.hasAttribute("notoverflowing"),
+    !win.gBrowser.tabContainer.arrowScrollbox.hasAttribute("overflowing"),
     "arrow scrollbox not overflowing"
   );
   await BrowserTestUtils.closeWindow(win);

browser/base/content/test/tabs/browser_overflowScroll.js

@@ -50,7 +50,7 @@ add_task(async function() {
   });
 
   ok(
-    !scrollbox.hasAttribute("notoverflowing"),
+    arrowScrollbox.hasAttribute("overflowing"),
     "Tab strip should be overflowing"
   );
 

toolkit/content/widgets/arrowscrollbox.js

@@ -143,7 +143,7 @@
         );
       }
 
-      this.setAttribute("notoverflowing", "true");
+      this.removeAttribute("overflowing");
       this.initializeAttributeInheritance();
       this._updateScrollButtonsDisabledState();
     }
@@ -557,7 +557,7 @@
     }
 
     _updateScrollButtonsDisabledState() {
-      if (this.hasAttribute("notoverflowing")) {
+      if (!this.hasAttribute("overflowing")) {
         this.setAttribute("scrolledtoend", "true");
         this.setAttribute("scrolledtostart", "true");
         return;
@@ -582,7 +582,7 @@
           let scrolledToStart = false;
           let scrolledToEnd = false;
 
-          if (this.hasAttribute("notoverflowing")) {
+          if (!this.hasAttribute("overflowing")) {
             scrolledToStart = true;
             scrolledToEnd = true;
           } else {
@@ -645,7 +645,7 @@
 
     on_wheel(event) {
       // Don't consume the event if we can't scroll.
-      if (this.hasAttribute("notoverflowing")) {
+      if (!this.hasAttribute("overflowing")) {
         return;
       }
 
@@ -750,10 +750,7 @@
       // Ignore underflow events:
       // - from nested scrollable elements
       // - corresponding to an overflow event that we ignored
-      if (
-        event.target != this.scrollbox ||
-        this.hasAttribute("notoverflowing")
-      ) {
+      if (event.target != this.scrollbox || !this.hasAttribute("overflowing")) {
         return;
       }
 
@@ -771,7 +768,7 @@
         return;
       }
 
-      this.setAttribute("notoverflowing", "true");
+      this.removeAttribute("overflowing");
       this._updateScrollButtonsDisabledState();
     }
 
@@ -796,7 +793,7 @@
         return;
       }
 
-      this.removeAttribute("notoverflowing");
+      this.setAttribute("overflowing", "true");
       this._updateScrollButtonsDisabledState();
     }
 

toolkit/themes/shared/scrollbox.css

@@ -6,8 +6,8 @@
 
 :host([scrolledtostart=true])::part(overflow-start-indicator),
 :host([scrolledtoend=true])::part(overflow-end-indicator),
-:host([notoverflowing=true]) .scrollbutton-up,
-:host([notoverflowing=true]) .scrollbutton-down {
+:host(:not([overflowing=true])) .scrollbutton-up,
+:host(:not([overflowing=true])) .scrollbutton-down {
   visibility: collapse;
 }