Add support for X11 workspaces

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 d2b27c9c18a675a16cae216ef469262f809ff120..be877fe86bbc960a76020fc818639107c410ece7 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -129,13 +129,13 @@ Widget::InitParams::InitParams(Type type)
       use_system_default_icon(false),
       show_state(ui::SHOW_STATE_DEFAULT),
       parent(nullptr),
+      workspace(-1),

[Elliot Glaysher, 2016/04/29 17:58:13]

Should the default value by -1? The docs for _NET_WM_DESKTOP say that the value
0xFFFFFFFF should be used for being placed on all desktops.

[Tom (Use chromium acct), 2016/04/29 19:14:04]

I use that as a sentinel because it's reserved.  In
desktop_window_tree_host_x11.cc, I only set the workspace if it's not -1.  I
guess this shouldn't matter anymore now that the int is going to chagne to a
string, and I'll just use the empty string as the default value.

[danakj, 2016/04/29 19:59:06]

Have you tested what happens if the chrome window is put on "all desktops" and
then you close/restore etc?

       native_widget(nullptr),
       desktop_window_tree_host(nullptr),
       layer_type(ui::LAYER_TEXTURED),
       context(nullptr),
       force_show_in_taskbar(false),
-      force_software_compositing(false) {
-}
+      force_software_compositing(false) {}
 
 Widget::InitParams::InitParams(const InitParams& other) = default;
 
@@ -1110,6 +1110,8 @@ void Widget::OnNativeWidgetSizeChanged(const gfx::Size& new_size) {
     GetWindowBoundsInScreen()));
 }
 
+void Widget::OnNativeWidgetWorkspaceChanged(int workspace_id) {}
+
 void Widget::OnNativeWidgetWindowShowStateChanged() {
   SaveWindowPlacementIfInitialized();
 }