exo: Improve window placement.

components/exo/wayland/server.cc

Index: components/exo/wayland/server.cc
diff --git a/components/exo/wayland/server.cc b/components/exo/wayland/server.cc
index c66325c23ffb1dcf36d18a00fc861d73532ee2fb..8a1ab15361312e2ab223c3dc0b53762fefad7942 100644
--- a/components/exo/wayland/server.cc
+++ b/components/exo/wayland/server.cc
@@ -638,7 +638,13 @@ void shell_surface_resize(wl_client* client,
 }
 
 void shell_surface_set_toplevel(wl_client* client, wl_resource* resource) {
-  GetUserDataAs<ShellSurface>(resource)->Init();
+  ShellSurface* shell_surface = GetUserDataAs<ShellSurface>(resource);
+
+  // Early out if shell surface has already been mapped.
+  if (shell_surface->enabled())
+    return;

[lpique, 2016/01/28 20:48:32]

Note: SetEnabled() basically does this same early out check (DRY).

[reveman, 2016/01/28 21:35:19]

Good point. Changed this to unconditionally call SetEnabled(true).

+
+  shell_surface->SetEnabled(true);
 }
 
 void shell_surface_set_transient(wl_client* client,
@@ -655,8 +661,14 @@ void shell_surface_set_fullscreen(wl_client* client,
                                   uint32_t method,
                                   uint32_t framerate,
                                   wl_resource* output_resource) {
-  GetUserDataAs<ShellSurface>(resource)->Init();
-  GetUserDataAs<ShellSurface>(resource)->SetFullscreen(true);
+  ShellSurface* shell_surface = GetUserDataAs<ShellSurface>(resource);
+
+  // Early out if shell surface has already been mapped.
+  if (shell_surface->enabled())
+    return;

[lpique, 2016/01/28 20:48:32]

If you remove this new check here or below (as above), note that
SetFullscreen/Maximize() do not check that if it is already full screen, though
this means that it is no worse than the code prior to this change.

[reveman, 2016/01/28 21:35:20]

Correct. It shouldn't be possible to change the state of a wl_shell_surface once
mapped if I understand the interface correctly but I changed the code to match
the old behavior and if we want to improve it we can instead do that in a
separate patch.

+
+  shell_surface->SetEnabled(true);
+  shell_surface->SetFullscreen(true);
 }
 
 void shell_surface_set_popup(wl_client* client,
@@ -673,8 +685,14 @@ void shell_surface_set_popup(wl_client* client,
 void shell_surface_set_maximized(wl_client* client,
                                  wl_resource* resource,
                                  wl_resource* output_resource) {
-  GetUserDataAs<ShellSurface>(resource)->Init();
-  GetUserDataAs<ShellSurface>(resource)->Maximize();
+  ShellSurface* shell_surface = GetUserDataAs<ShellSurface>(resource);
+
+  // Early out if shell surface has already been mapped.
+  if (shell_surface->enabled())
+    return;
+
+  shell_surface->SetEnabled(true);
+  shell_surface->Maximize();
 }
 
 void shell_surface_set_title(wl_client* client,
@@ -725,6 +743,10 @@ void shell_get_shell_surface(wl_client* client,
     return;
   }
 
+  // Shell surfaces are initially disabled and needs to be explicitly mapped
+  // before they are enabled and can become visible.
+  shell_surface->SetEnabled(false);
+
   shell_surface->set_surface_destroyed_callback(base::Bind(
       &wl_resource_destroy, base::Unretained(shell_surface_resource)));
 
@@ -952,9 +974,6 @@ void xdg_shell_get_xdg_surface(wl_client* client,
     return;
   }
 
-  // An XdgSurface is a toplevel shell surface.
-  shell_surface->Init();
-
   shell_surface->set_close_callback(base::Bind(
       &xdg_surface_send_close, base::Unretained(xdg_surface_resource)));