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

chrome/browser/infobars/infobar_container.h

 // Copyright (c) 2011 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_BROWSER_INFOBARS_INFOBAR_CONTAINER_H_
 #define CHROME_BROWSER_INFOBARS_INFOBAR_CONTAINER_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/time.h"
-#include "chrome/browser/ui/search/instant_overlay_model_observer.h"
 #include "chrome/browser/ui/search/search_model_observer.h"
 #include "chrome/common/search_types.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 class InfoBar;
 class InfoBarDelegate;
 class InfoBarService;
 
@@ skipping 20 matching lines @@
 //   TODO(kuan): this scenario requires more complex synchronization with
 //   renderer SearchBoxAPI and will be implemented as the next step;
 //   for now, hiding is immediate.
 // When the user changes back out of |SEARCH_SUGGESTIONS| mode, it reshows any
 // infobars, and starts a 50 ms window during which any attempts to re-hide any
 // infobars are handled without animation.  This prevents glitchy-looking
 // behavior when the user navigates following a mode change, which otherwise
 // would re-show the infobars only to instantly animate them closed.  The window
 // to re-hide infobars without animation is canceled if a tab change occurs.
 class InfoBarContainer : public content::NotificationObserver,
-                         public chrome::search::SearchModelObserver,
-                         public InstantOverlayModelObserver {
+                         public chrome::search::SearchModelObserver {
  public:
   class Delegate {
    public:
     // The separator color may vary depending on where the container is hosted.
     virtual SkColor GetInfoBarSeparatorColor() const = 0;
 
     // The delegate is notified each time the infobar container changes height,
     // as well as when it stops animating.
     virtual void InfoBarContainerStateChanged(bool is_animating) = 0;
 
@@ skipping 38 matching lines @@
   // anything necessary to respond, e.g. re-layout.
   void OnInfoBarStateChanged(bool is_animating);
 
   // Called by |infobar| to request that it be removed from the container, as it
   // is about to delete itself.  At this point, |infobar| should already be
   // hidden.
   void RemoveInfoBar(InfoBar* infobar);
 
   const Delegate* delegate() const { return delegate_; }
 
-  // InstantOverlayModelObserver:
-  virtual void OverlayStateChanged(const InstantOverlayModel& model) OVERRIDE;
-
  protected:
   // Subclasses must call this during destruction, so that we can remove
   // infobars (which will call the pure virtual functions below) while the
   // subclass portion of |this| has not yet been destroyed.
   void RemoveAllInfoBarsForDestruction();
 
   // These must be implemented on each platform to e.g. adjust the visible
   // object hierarchy.
   virtual void PlatformSpecificAddInfoBar(InfoBar* infobar,
                                           size_t position) = 0;
   virtual void PlatformSpecificRemoveInfoBar(InfoBar* infobar) = 0;
   virtual void PlatformSpecificInfoBarStateChanged(bool is_animating) {}
 
  private:
   typedef std::vector<InfoBar*> InfoBars;
 
   // content::NotificationObserver:
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // chrome::search::SearchModelObserver:
-  virtual void ModeChanged(const chrome::search::Mode& old_mode,
-                           const chrome::search::Mode& new_mode) OVERRIDE;
+  virtual void ModelChanged(
+      const chrome::search::SearchModel::State& old_state,
+      const chrome::search::SearchModel::State& new_state) OVERRIDE;
 
   // Hides an InfoBar for the specified delegate, in response to a notification
   // from the selected InfoBarService.  The InfoBar's disappearance will be
   // animated if |use_animation| is true and it has been more than 50ms since
   // infobars were reshown due to an Instant Extended mode change. The InfoBar
   // will call back to RemoveInfoBar() to remove itself once it's hidden (which
   // may mean synchronously).  Returns the position within |infobars_| the
   // infobar was previously at.
   size_t HideInfoBar(InfoBarDelegate* delegate, bool use_animation);
 
@@ skipping 30 matching lines @@
   // Extended.
   chrome::search::SearchModel* search_model_;
 
   // Calculated in SetMaxTopArrowHeight().
   int top_arrow_target_height_;
 
   DISALLOW_COPY_AND_ASSIGN(InfoBarContainer);
 };
 
 #endif  // CHROME_BROWSER_INFOBARS_INFOBAR_CONTAINER_H_