Panels refactor: Support browserless panels on Linux.

chrome/browser/ui/panels/panel_drag_browsertest.cc

Index: chrome/browser/ui/panels/panel_drag_browsertest.cc
diff --git a/chrome/browser/ui/panels/panel_drag_browsertest.cc b/chrome/browser/ui/panels/panel_drag_browsertest.cc
index a166f79355c65c4fb0656c11ea094205a4afd5e0..417b2f48fe7ed667e45f2cdfedaf1930806cdd01 100644
--- a/chrome/browser/ui/panels/panel_drag_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_drag_browsertest.cc
@@ -12,9 +12,6 @@
 #include "chrome/browser/ui/panels/panel_manager.h"
 #include "chrome/browser/ui/panels/test_panel_mouse_watcher.h"
 
-// Refactor has only been done for Win and Mac panels so far.
-#if defined(OS_WIN) || defined(OS_MACOSX)
-
 class PanelDragBrowserTest : public BasePanelBrowserTest {
  public:
   PanelDragBrowserTest() : BasePanelBrowserTest() {
@@ -1344,5 +1341,3 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, DragDetachedPanelToTop) {
 
   panel_manager->CloseAll();
 }
-
-#endif // OS_WIN || OS_MACOSX