Added back button when in folder view.

ui/app_list/views/search_box_view.cc

Index: ui/app_list/views/search_box_view.cc
diff --git a/ui/app_list/views/search_box_view.cc b/ui/app_list/views/search_box_view.cc
index 7841388bd63fffa5cdfefc49a25236866a59fb02..7ede992bacce4e176ca31e4d6eaf5b4544ef5e9a 100644
--- a/ui/app_list/views/search_box_view.cc
+++ b/ui/app_list/views/search_box_view.cc
@@ -182,17 +182,19 @@ SearchBoxView::SearchBoxView(SearchBoxViewDelegate* delegate,
     search_box_->set_placeholder_text_draw_flags(
         gfx::Canvas::TEXT_ALIGN_CENTER);
     search_box_->SetFontList(search_box_->GetFontList().DeriveWithSizeDelta(2));
+  }
+  back_button_ = new SearchBoxImageButton(this);
+  ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
+  back_button_->SetImage(views::ImageButton::STATE_NORMAL,
+                         rb.GetImageSkiaNamed(IDR_APP_LIST_FOLDER_BACK_NORMAL));
+  back_button_->SetImageAlignment(views::ImageButton::ALIGN_CENTER,
+                                  views::ImageButton::ALIGN_MIDDLE);
+  SetBackButtonLabel(false);
+
+  if (is_fullscreen_app_list_enabled_) {
+    content_container_->AddChildView(google_icon_);

[vadimt, 2017/06/22 18:28:08]

Google icon is supposed to be owned by view hierarchy, but you may never add it
to the hierarchy, so it will be leaked?

Please run with ASAN to confirm the leak, then consider unique_ptr +
set_owned_by_client().

[newcomer, 2017/06/23 23:28:08]

I took xiyuan@'s suggestion of setting the visibility of the views. 

   } else {
-    back_button_ = new SearchBoxImageButton(this);
-    ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
-    back_button_->SetImage(
-        views::ImageButton::STATE_NORMAL,
-        rb.GetImageSkiaNamed(IDR_APP_LIST_FOLDER_BACK_NORMAL));
-    back_button_->SetImageAlignment(views::ImageButton::ALIGN_CENTER,
-                                    views::ImageButton::ALIGN_MIDDLE);
-    SetBackButtonLabel(false);
     content_container_->AddChildView(back_button_);
-
     search_box_->set_placeholder_text_color(kHintTextColor);
   }
   content_container_->AddChildView(search_box_);
@@ -332,6 +334,22 @@ void SearchBoxView::SetBackButtonLabel(bool folder) {
   back_button_->SetTooltipText(back_button_label);
 }
 
+void SearchBoxView::ShowBackOrGoogleIcon(bool show_back_button) {
+  if (!is_fullscreen_app_list_enabled_)
+    return;
+
+  if (show_back_button) {
+    content_container_->AddChildViewAt(
+        back_button_, content_container_->GetIndexOf(google_icon_));
+    content_container_->RemoveChildView(google_icon_);
+  } else {
+    content_container_->AddChildViewAt(
+        google_icon_, content_container_->GetIndexOf(back_button_));
+    content_container_->RemoveChildView(back_button_);

[xiyuan, 2017/06/22 17:33:24]

The current code assumes |google_icon_| and |back_button_| are owned by the
views hierarchy. Remove them from the hierachy leaves them unowned and could
result in a memory leak.

Can we manipulate visibility instead? If we want to do the add/remove trick, we
need to make SearchBoxView owns the two.

[newcomer, 2017/06/23 23:28:08]

I set the visibility as that makes more sense to me.

+  }
+  content_container_->Layout();
+}
+
 bool SearchBoxView::OnMouseWheel(const ui::MouseWheelEvent& event) {
   if (contents_view_)
     return contents_view_->OnMouseWheel(event);