alternate ntp: implement Show/HideBars API to reduce jank when showing/hiding bars

chrome/renderer/searchbox/searchbox.h

 // Copyright 2012 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.
 
 #ifndef CHROME_RENDERER_SEARCHBOX_SEARCHBOX_H_
 #define CHROME_RENDERER_SEARCHBOX_SEARCHBOX_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 43 matching lines @@
   // Sends ChromeViewHostMsg_SearchBoxDeleteMostVisitedItem to the browser.
   void DeleteMostVisitedItem(uint64 most_visited_item_id);
 
   // Sends ChromeViewHostMsg_SearchBoxUndoMostVisitedDeletion to the browser.
   void UndoMostVisitedDeletion(uint64 most_visited_item_id);
 
   // Sends ChromeViewHostMsg_SearchBoxUndoAllMostVisitedDeletions to the
   // browser.
   void UndoAllMostVisitedDeletions();
 
+  // Shows any attached bars.
+  void ShowBars();
+
+  // Hides any attached bars.  When the bars are hidden, the "onbarshidden"
+  // event is fired to notify the page.
+  void HideBars();
+
   const string16& query() const { return query_; }
   bool verbatim() const { return verbatim_; }
   size_t selection_start() const { return selection_start_; }
   size_t selection_end() const { return selection_end_; }
   int results_base() const { return results_base_; }
   bool is_key_capture_enabled() const { return is_key_capture_enabled_; }
   bool display_instant_results() const { return display_instant_results_; }
   const string16& omnibox_font() const { return omnibox_font_; }
   size_t omnibox_font_size() const { return omnibox_font_size_; }
 
@@ skipping 19 matching lines @@
   virtual void DidClearWindowObject(WebKit::WebFrame* frame) OVERRIDE;
 
   void OnChange(const string16& query,
                 bool verbatim,
                 size_t selection_start,
                 size_t selection_end);
   void OnSubmit(const string16& query);
   void OnCancel(const string16& query);
   void OnPopupResize(const gfx::Rect& bounds);
   void OnMarginChange(int margin, int width);
+  void OnBarsHidden();
   void OnDetermineIfPageSupportsInstant();
   void OnAutocompleteResults(
       const std::vector<InstantAutocompleteResult>& results);
   void OnUpOrDownKeyPressed(int count);
   void OnCancelSelection(const string16& query);
   void OnKeyCaptureChange(bool is_key_capture_enabled);
   void OnSetDisplayInstantResults(bool display_instant_results);
   void OnThemeChanged(const ThemeBackgroundInfo& theme_info);
   void OnThemeAreaHeightChanged(int height);
   void OnFontInformationReceived(const string16& omnibox_font,
@@ skipping 21 matching lines @@
   ThemeBackgroundInfo theme_info_;
   bool display_instant_results_;
   string16 omnibox_font_;
   size_t omnibox_font_size_;
   std::vector<InstantMostVisitedItem> most_visited_items_;
 
   DISALLOW_COPY_AND_ASSIGN(SearchBox);
 };
 
 #endif  // CHROME_RENDERER_SEARCHBOX_SEARCHBOX_H_