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

chrome/browser/ui/views/frame/instant_overlay_controller_views.cc

 // 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.
 
 #include "chrome/browser/ui/views/frame/instant_overlay_controller_views.h"
 
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/search/search.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/search/instant_overlay_model.h"
+#include "chrome/browser/ui/search/search_model.h"
+#include "chrome/browser/ui/search/search_tab_helper.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/view_ids.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/frame/contents_container.h"
 #include "chrome/browser/ui/views/infobars/infobar_container_view.h"
 #include "ui/views/controls/webview/webview.h"
 
 InstantOverlayControllerViews::InstantOverlayControllerViews(
     Browser* browser,
     ContentsContainer* contents)
     : InstantOverlayController(browser),
       contents_(contents) {
 }
 
 InstantOverlayControllerViews::~InstantOverlayControllerViews() {
 }
 
 void InstantOverlayControllerViews::OverlayStateChanged(
     const InstantOverlayModel& model) {
+  // Set top bars (bookmark and info bars) visibility if Instant Extended API
+  // is enabled.
+  bool set_top_bars_visibility = chrome::search::IsInstantExtendedAPIEnabled();
+
   if (model.mode().is_ntp() || model.mode().is_search_suggestions()) {
     // Show the overlay.
     if (!overlay_) {
       overlay_.reset(new views::WebView(browser_->profile()));
       overlay_->set_id(VIEW_ID_TAB_CONTAINER);
     }
     // Drop shadow is only needed if search mode is not |NTP| and overlay does
     // not fill up the entire contents page.
     bool draw_drop_shadow = !model.mode().is_ntp() &&
         !(contents_->IsOverlayFullHeight(model.height(), model.height_units()));
     content::WebContents* web_contents = model.GetOverlayContents();
     contents_->SetOverlay(overlay_.get(), web_contents, model.height(),
                           model.height_units(), draw_drop_shadow);
     overlay_->SetWebContents(web_contents);
   } else if (overlay_) {
     // Hide the overlay. SetWebContents() must happen before SetOverlay().
     overlay_->SetWebContents(NULL);
     contents_->SetOverlay(NULL, NULL, 100, INSTANT_SIZE_PERCENT, false);
     overlay_.reset();
+  } else {
+    // Don't set top bars visiblility if nothing was done with overlay.
+    set_top_bars_visibility = false;
   }
 
-  browser_->MaybeUpdateBookmarkBarStateForInstantOverlay(model.mode());
+  if (set_top_bars_visibility) {
+    // Set top bars visibility for current tab via |SearchTabHelper| of current
+    // active web contents: top bars are hidden if there's overlay.
+    chrome::search::SearchTabHelper* search_tab_helper =
+        chrome::search::SearchTabHelper::FromWebContents(
+            browser_->tab_strip_model()->GetActiveWebContents());
+    if (search_tab_helper)
+      search_tab_helper->model()->SetTopBarsVisible(!overlay_);
+  }
 
   // If an Instant overlay is added during an immersive mode reveal, the reveal
   // view needs to stay on top.
-  // Notify infobar container of change in overlay state.
   if (overlay_) {
     BrowserView* browser_view = BrowserView::GetBrowserViewForBrowser(browser_);
-    if (browser_view) {
+    if (browser_view)
       browser_view->MaybeStackImmersiveRevealAtTop();
-      browser_view->infobar_container()->OverlayStateChanged(model);
-    }
   }
 }