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

chrome/renderer/searchbox/searchbox.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/renderer/searchbox/searchbox.h"
 
 #include "base/utf_string_conversions.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/renderer/searchbox/searchbox_extension.h"
@@ skipping 73 matching lines @@
   render_view()->Send(new ChromeViewHostMsg_SearchBoxUndoMostVisitedDeletion(
       render_view()->GetRoutingID(), most_visited_item_id));
 }
 
 void SearchBox::UndoAllMostVisitedDeletions() {
   render_view()->Send(
       new ChromeViewHostMsg_SearchBoxUndoAllMostVisitedDeletions(
       render_view()->GetRoutingID()));
 }
 
+void SearchBox::ShowBars() {
+  DVLOG(1) << render_view() << " ShowBars";
+  render_view()->Send(new ChromeViewHostMsg_SearchBoxShowBars(
+      render_view()->GetRoutingID(), render_view()->GetPageId()));
+}
+
+void SearchBox::HideBars() {
+  DVLOG(1) << render_view() << " HideBars";
+  render_view()->Send(new ChromeViewHostMsg_SearchBoxHideBars(
+      render_view()->GetRoutingID(), render_view()->GetPageId()));
+}
+
 int SearchBox::GetStartMargin() const {
   return static_cast<int>(start_margin_ / GetZoom());
 }
 
 gfx::Rect SearchBox::GetPopupBounds() const {
   double zoom = GetZoom();
   return gfx::Rect(static_cast<int>(popup_bounds_.x() / zoom),
                    static_cast<int>(popup_bounds_.y() / zoom),
                    static_cast<int>(popup_bounds_.width() / zoom),
                    static_cast<int>(popup_bounds_.height() / zoom));
@@ skipping 24 matching lines @@
 }
 
 bool SearchBox::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(SearchBox, message)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxChange, OnChange)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxSubmit, OnSubmit)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxCancel, OnCancel)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxPopupResize, OnPopupResize)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxMarginChange, OnMarginChange)
+    IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxBarsHidden, OnBarsHidden)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_DetermineIfPageSupportsInstant,
                         OnDetermineIfPageSupportsInstant)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxAutocompleteResults,
                         OnAutocompleteResults)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxUpOrDownKeyPressed,
                         OnUpOrDownKeyPressed)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxCancelSelection,
                         OnCancelSelection)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SearchBoxSetDisplayInstantResults,
                         OnSetDisplayInstantResults)
@@ skipping 70 matching lines @@
 
   // Override only the width parameter of the popup bounds.
   popup_bounds_.set_width(width);
 
   if (render_view()->GetWebView() && render_view()->GetWebView()->mainFrame()) {
     extensions_v8::SearchBoxExtension::DispatchMarginChange(
         render_view()->GetWebView()->mainFrame());
   }
 }
 
+void SearchBox::OnBarsHidden() {
+  if (render_view()->GetWebView() && render_view()->GetWebView()->mainFrame()) {
+    extensions_v8::SearchBoxExtension::DispatchBarsHidden(
+        render_view()->GetWebView()->mainFrame());
+  }
+}
+
 void SearchBox::OnDetermineIfPageSupportsInstant() {
   if (render_view()->GetWebView() && render_view()->GetWebView()->mainFrame()) {
     bool result = extensions_v8::SearchBoxExtension::PageSupportsInstant(
         render_view()->GetWebView()->mainFrame());
     DVLOG(1) << render_view() << " PageSupportsInstant: " << result;
     render_view()->Send(new ChromeViewHostMsg_InstantSupportDetermined(
         render_view()->GetRoutingID(), render_view()->GetPageId(), result));
   }
 }
 
@@ skipping 110 matching lines @@
   if (render_view()->GetWebView() && render_view()->GetWebView()->mainFrame()) {
     extensions_v8::SearchBoxExtension::DispatchMostVisitedChanged(
         render_view()->GetWebView()->mainFrame());
   }
 }
 
 const std::vector<InstantMostVisitedItem>&
 SearchBox::GetMostVisitedItems() const {
   return most_visited_items_;
 }