ash: Rename LauncherIconObserver to ShelfIconObserver.

ash/launcher/launcher.cc

Index: ash/launcher/launcher.cc
diff --git a/ash/launcher/launcher.cc b/ash/launcher/launcher.cc
index 9637acb018702390415af0f0211c7206255d5520..e9817098c064da3daa5727f7ed7c7de00795b5c8 100644
--- a/ash/launcher/launcher.cc
+++ b/ash/launcher/launcher.cc
@@ -121,11 +121,11 @@ void Launcher::CycleWindowLinear(CycleDirection direction) {
     ActivateLauncherItem(item_index);
 }
 
-void Launcher::AddIconObserver(LauncherIconObserver* observer) {
+void Launcher::AddIconObserver(ShelfIconObserver* observer) {
   shelf_view_->AddIconObserver(observer);
 }
 
-void Launcher::RemoveIconObserver(LauncherIconObserver* observer) {
+void Launcher::RemoveIconObserver(ShelfIconObserver* observer) {
   shelf_view_->RemoveIconObserver(observer);
 }