Bug 1419442 - [Linux/Titlebar rendering] Add optional drag space above titlebar, r=dao

MozReview-Commit-ID: KkKXcrIPFhg

--HG--
extra : rebase_source : a88228edcdc3cfeebb3ebb041cbc206ff7c1a794

browser/themes/linux/browser.css

@@ -654,6 +654,20 @@ notification[value="translation"] menulist > .menulist-dropmarker {
     -moz-appearance: -moz-window-titlebar-maximized;
   }
 
+  /* Add extra space to titlebar for dragging */
+  :root[sizemode="normal"][chromehidden~="menubar"] #TabsToolbar,
+  :root[sizemode="normal"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar {
+    margin-top: var(--space-above-tabbar);
+  }
+
+  /* Private browsing and accessibility indicators */
+  :root[sizemode="normal"][chromehidden~="menubar"] #TabsToolbar > .private-browsing-indicator,
+  :root[sizemode="normal"][chromehidden~="menubar"] #TabsToolbar > .accessibility-indicator,
+  :root[sizemode="normal"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar > .private-browsing-indicator,
+  :root[sizemode="normal"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar > .accessibility-indicator {
+    margin-top: calc(-1 * var(--space-above-tabbar));
+  }
+
   /* The button box must appear on top of the navigator-toolbox in order for
    * click and hover mouse events to work properly for the button in the restored
    * window state. Otherwise, elements in the navigator-toolbox, like the menubar,