On Linux, the App Launcher is now shown in the taskbar.

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 179ccc656c976d34dd0ef54154596c2007dcdf74..c2509610f25838aadbb0c958d0cf2d352de66e98 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -128,7 +128,8 @@ Widget::InitParams::InitParams()
       desktop_root_window_host(NULL),
       top_level(false),
       layer_type(ui::LAYER_TEXTURED),
-      context(NULL) {
+      context(NULL),
+      force_show_in_taskbar(false) {
 }
 
 Widget::InitParams::InitParams(Type type)
@@ -152,7 +153,8 @@ Widget::InitParams::InitParams(Type type)
       desktop_root_window_host(NULL),
       top_level(false),
       layer_type(ui::LAYER_TEXTURED),
-      context(NULL) {
+      context(NULL),
+      force_show_in_taskbar(false) {
 }
 
 Widget::InitParams::~InitParams() {