App list: TileItemView::SetAppListItem exits early if item already set.

ui/app_list/views/tile_item_view.cc

Index: ui/app_list/views/tile_item_view.cc
diff --git a/ui/app_list/views/tile_item_view.cc b/ui/app_list/views/tile_item_view.cc
index 583098e25cad9b879cba0a5c81e3e3b64971df96..d770e8102f5a0b8e09348460acd4c6449831a6f4 100644
--- a/ui/app_list/views/tile_item_view.cc
+++ b/ui/app_list/views/tile_item_view.cc
@@ -94,6 +94,10 @@ TileItemView::TileItemView()
   title_->SetFontList(rb.GetFontList(kItemTextFontStyle));
   title_->SetHorizontalAlignment(gfx::ALIGN_CENTER);
 
+  // When |item_| is NULL, the tile is invisible. Calling SetAppListItem with a
+  // non-NULL item makes the tile visible.
+  SetVisible(false);

[Matt Giuca, 2014/06/16 00:29:28]

I don't think adding this actually changes any behaviour (since SetAppListItem
appears to always be called as soon as this guy is created), but it's good to
have it for consistent state, as noted in the comment.

Without this, the test fails because calling SetAppListItem(NULL) will no longer
make the tile invisible. If we make the tile start out invisible, then the
early-exit behaviour in SetAppListItem(NULL) is correct.

+
   AddChildView(icon_);
   AddChildView(title_);
 }
@@ -102,6 +106,12 @@ TileItemView::~TileItemView() {
 }
 
 void TileItemView::SetAppListItem(AppListItem* item) {
+  // TODO(calamity): This will not update if the contents of |item_| have
+  // changed since it was last assigned. Add an observer to refresh when the
+  // item changes.
+  if (item == item_)
+    return;
+
   item_ = item;
   if (!item) {
     SetVisible(false);