compositor: Remove shell->activate callback

It's all internal to the shell plugin now.
diff --git a/compositor/compositor.h b/compositor/compositor.h
index 793a0c8..1741879 100644
--- a/compositor/compositor.h
+++ b/compositor/compositor.h
@@ -148,9 +148,6 @@
 };
 
 struct wlsc_shell {
-	void (*activate)(struct wlsc_shell *shell,
-			 struct wlsc_surface *es,
-			 struct wlsc_input_device *device, uint32_t time);
 	void (*lock)(struct wlsc_shell *shell);
 	void (*unlock)(struct wlsc_shell *shell);
 	void (*map)(struct wlsc_shell *shell, struct wlsc_surface *surface,
diff --git a/compositor/shell.c b/compositor/shell.c
index db92b5e..ee15ddf 100644
--- a/compositor/shell.c
+++ b/compositor/shell.c
@@ -861,8 +861,7 @@
 
 	focus = (struct wlsc_surface *) device->pointer_focus;
 	if (state && focus && device->grab == NULL)
-		compositor->shell->activate(compositor->shell,
-					    focus, wd, time);
+		activate(compositor->shell, focus, wd, time);
 }
 
 static void
@@ -1249,7 +1248,6 @@
 
 	memset(shell, 0, sizeof *shell);
 	shell->compositor = ec;
-	shell->shell.activate = activate;
 	shell->shell.lock = lock;
 	shell->shell.unlock = unlock;
 	shell->shell.map = map;
diff --git a/compositor/tablet-shell.c b/compositor/tablet-shell.c
index 6901acd..54985b2 100644
--- a/compositor/tablet-shell.c
+++ b/compositor/tablet-shell.c
@@ -389,13 +389,6 @@
 }
 
 static void
-tablet_shell_activate(struct wlsc_shell *base, struct wlsc_surface *es,
-		      struct wlsc_input_device *device, uint32_t time)
-{
-	wlsc_surface_activate(es, device, time);
-}
-
-static void
 tablet_shell_lock(struct wlsc_shell *base)
 {
 	struct tablet_shell *shell =
@@ -555,7 +548,6 @@
 
 	compositor->shell = &shell->shell;
 
-	shell->shell.activate = tablet_shell_activate;
 	shell->shell.lock = tablet_shell_lock;
 	shell->shell.unlock = tablet_shell_unlock;
 	shell->shell.map = tablet_shell_map;