Bug 1575238 - Remove tabs-newtab-button class. r=mikedeboer

Differential Revision: https://phabricator.services.mozilla.com/D42656

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

browser/base/content/browser.css

@@ -139,9 +139,9 @@ panelview[mainview] > .panel-header {
 
 #tabbrowser-tabs:not([overflow="true"]):not([hashiddentabs]) ~ #alltabs-button,
 #tabbrowser-tabs[hasadjacentnewtabbutton]:not([overflow="true"]) ~ #new-tab-button,
-#tabbrowser-tabs[overflow="true"] > .tabbrowser-arrowscrollbox > .tabs-newtab-button,
-#tabbrowser-tabs:not([hasadjacentnewtabbutton]) > .tabbrowser-arrowscrollbox > .tabs-newtab-button,
-#TabsToolbar[customizing="true"] #tabbrowser-tabs > .tabbrowser-arrowscrollbox > .tabs-newtab-button {
+#tabbrowser-tabs[overflow="true"] > .tabbrowser-arrowscrollbox > #tabs-newtab-button,
+#tabbrowser-tabs:not([hasadjacentnewtabbutton]) > .tabbrowser-arrowscrollbox > #tabs-newtab-button,
+#TabsToolbar[customizing="true"] #tabs-newtab-button {
   visibility: collapse;
 }
 

browser/base/content/browser.xhtml

@@ -736,7 +736,7 @@
               <arrowscrollbox orient="horizontal" flex="1" style="min-width: 1px;" clicktoscroll="true" class="tabbrowser-arrowscrollbox" scrolledtostart="true" scrolledtoend="true">
                 <tab is="tabbrowser-tab" class="tabbrowser-tab" selected="true" visuallyselected="true" fadein="true"/>
                 <toolbarbutton id="tabs-newtab-button"
-                               class="tabs-newtab-button toolbarbutton-1"
+                               class="toolbarbutton-1"
                                command="cmd_newNavigatorTab"
                                onclick="checkForMiddleClick(this, event);"
                                tooltip="dynamic-shortcut-tooltip"/>

browser/base/content/tabbrowser-tabs.js

@@ -906,7 +906,7 @@
     }
 
     get newTabButton() {
-      return this.querySelector(".tabs-newtab-button");
+      return this.querySelector("#tabs-newtab-button");
     }
 
     // Accessor for tabs.  arrowScrollbox has two non-tab elements at the

browser/themes/shared/tabs.inc.css

@@ -706,7 +706,7 @@
 
 /* New tab button */
 
-.tabs-newtab-button,
+#tabs-newtab-button,
 #TabsToolbar #new-tab-button {
   list-style-image: url(chrome://browser/skin/add.svg);
 }

testing/marionette/puppeteer/firefox/firefox_puppeteer/ui/browser/tabbar.py

@@ -36,7 +36,7 @@ class TabBar(UIBaseLib):
 
         :returns: Reference to the new tab button.
         """
-        return self.toolbar.find_element(By.CLASS_NAME, 'tabs-newtab-button')
+        return self.toolbar.find_element(By.ID, 'tabs-newtab-button')
 
     @property
     def tabs(self):