Recreate the loader as soon as it is deleted and ensure that it does not become stale.

chrome/browser/instant/instant_controller.h

 // Copyright (c) 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_BROWSER_INSTANT_INSTANT_CONTROLLER_H_
 #define CHROME_BROWSER_INSTANT_INSTANT_CONTROLLER_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/string16.h"
 #include "base/timer.h"
 #include "chrome/browser/instant/instant_commit_type.h"
 #include "chrome/browser/instant/instant_loader_delegate.h"
 #include "chrome/common/instant_types.h"
 #include "content/public/common/page_transition_types.h"
 #include "googleurl/src/gurl.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/rect.h"
@@ skipping 122 matching lines @@
   virtual void SwappedTabContents(InstantLoader* loader) OVERRIDE;
   virtual void InstantLoaderContentsFocused(InstantLoader* loader) OVERRIDE;
 
 #if defined(UNIT_TEST)
   // Accessors used only in tests.
   bool is_showing() const { return is_showing_; }
   InstantLoader* loader() const { return loader_.get(); }
 #endif
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(InstantTest, InstantLoaderRefresh);
+
   // Creates a new loader if necessary (for example, if the |instant_url| has
   // changed since the last time we created the loader).
   void ResetLoader(const std::string& instant_url,
                    const TabContents* active_tab);
 
+  // Ensures that the |loader_| uses the default Instant URL, recreating it if
+  // necessary. Will not do anything if the Instant URL could not be determined
+  // or the active tab is NULL (browser is shutting down).
+  void CreateDefaultLoader();
+
+  // If the |loader_| is not showing, it is deleted and recreated. Else the
+  // refresh is skipped and the next refresh is scheduled.
+  void OnStaleLoader();
+
+  // Calls OnStaleLoader if |stale_loader_timer_| is not running.
+  void MaybeOnStaleLoader();
+
   // Destroys the |loader_| and its preview contents.
   void DeleteLoader();
 
   // Counterpart to Hide(). Asks the |delegate_| to display the preview.
   void Show();
 
   // Send the omnibox dropdown bounds to the page.
   void SendBoundsToPage();
 
   // If |template_url| is a valid TemplateURL for use with Instant, fills in
@@ skipping 48 matching lines @@
 
   // Current omnibox bounds.
   gfx::Rect omnibox_bounds_;
 
   // Last bounds passed to the page.
   gfx::Rect last_omnibox_bounds_;
 
   // Timer used to update the bounds of the omnibox.
   base::OneShotTimer<InstantController> update_bounds_timer_;
 
+  // Timer used to ensure that the Instant page does not get too stale.
+  base::OneShotTimer<InstantController> stale_loader_timer_;
+
   // For each key K => value N, the map says that we found that the search
   // engine identified by Instant URL K didn't support the Instant API in each
   // of the last N times that we loaded it. If an Instant URL isn't present in
   // the map at all or has a value 0, it means that search engine supports the
   // Instant API (or we assume it does, since we haven't determined it doesn't).
   std::map<std::string, int> blacklisted_urls_;
 
   // Search terms extraction (for autocomplete history matches) doesn't work
   // on Instant URLs. So, whenever the user commits an Instant search, we add
   // an equivalent non-Instant search URL to history, so that the search shows
   // up in autocomplete history matches.
   GURL url_for_history_;
 
   DISALLOW_COPY_AND_ASSIGN(InstantController);
 };
 
 #endif  // CHROME_BROWSER_INSTANT_INSTANT_CONTROLLER_H_