Add a DummySearchBoxView to the experimental app list start page.

ui/app_list/views/app_list_main_view.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/views/app_list_main_view.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 151 matching lines @@
   pending_icon_loaders_.clear();
   model_ = delegate_->GetModel();
   search_box_view_->ModelChanged();
   delete contents_view_;
   contents_view_ = NULL;
   AddContentsView();
   Layout();
 }
 
 void AppListMainView::UpdateSearchBoxVisibility() {
-  search_box_view_->SetVisible(
+  bool visible =
       !contents_view_->IsNamedPageActive(ContentsView::NAMED_PAGE_START) ||
-      contents_view_->IsShowingSearchResults());
+      contents_view_->IsShowingSearchResults();
+  search_box_view_->SetVisible(visible);
+  if (visible)
+    search_box_view_->search_box()->RequestFocus();
 }
 
-void AppListMainView::OnStartPageSearchButtonPressed() {
+void AppListMainView::OnStartPageSearchTextfieldChanged(
+    const base::string16& new_contents) {
   search_box_view_->SetVisible(true);
-  search_box_view_->search_box()->SetText(base::string16());
-  search_box_view_->RequestFocus();
+  search_box_view_->search_box()->SetText(new_contents);

[tapted, 2014/06/18 02:46:05]

will this trigger AppListMainView::QueryChanged(SearchBoxView* sender)? If yes,
the lines above and below are probably redundant, since QueryChanged calls
UpdateSearchBoxVisibility

[calamity, 2014/06/18 06:49:40]

Unfortunately QueryChanged() isn't triggered by SetText() as part of Textfield's
design.

+  search_box_view_->search_box()->RequestFocus();
 }
 
 void AppListMainView::SetDragAndDropHostOfCurrentAppList(
     ApplicationDragAndDropHost* drag_and_drop_host) {
   contents_view_->SetDragAndDropHostOfCurrentAppList(drag_and_drop_host);
 }
 
 bool AppListMainView::ShouldCenterWindow() const {
   return delegate_->ShouldCenterWindow();
 }
@@ skipping 94 matching lines @@
   // Resubmit the query via a posted task so that all observers for the
   // uninstall notification are notified.
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&AppListMainView::QueryChanged,
                  weak_ptr_factory_.GetWeakPtr(),
                  search_box_view_));
 }
 
 }  // namespace app_list