Add core plumbing for Instant Extended work

chrome/browser/ui/search/search_tab_helper.h

Index: chrome/browser/ui/search/search_tab_helper.h
diff --git a/chrome/browser/ui/search/search_tab_helper.h b/chrome/browser/ui/search/search_tab_helper.h
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+// 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_UI_SEARCH_SEARCH_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_SEARCH_SEARCH_TAB_HELPER_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/web_contents_observer.h"
+
+class AutocompleteEditModel;
+class TabContents;
+
+namespace content {
+class RenderWidgetHost;
+}
+
+namespace chrome {
+namespace search {
+
+class SearchModel;
+
+// Per-tab search "helper".  Acts as the owner and controller of the tab's
+// search UI model.
+class SearchTabHelper : public content::WebContentsObserver,
+                        public content::NotificationObserver {
+ public:
+  SearchTabHelper(TabContents* contents, bool is_search_enabled);
+  virtual ~SearchTabHelper();
+
+  SearchModel* model() const {
+    return model_.get();
+  }
+
+  // Invoked when the AutocompleteEditModel changes state in some way that might
+  // affect the search mode.
+  void AutocompleteEditModelChanged(AutocompleteEditModel* edit_model);
+
+  // content::WebContentsObserver overrides:
+  virtual void NavigateToPendingEntry(
+      const GURL& url,
+      content::NavigationController::ReloadType reload_type) OVERRIDE;
+  virtual void DidStartProvisionalLoadForFrame(
+      int64 frame_id,
+      bool is_main_frame,
+      const GURL& validated_url,
+      bool is_error_page,
+      content::RenderViewHost* render_view_host) OVERRIDE;
+  virtual void DocumentLoadedInFrame(int64 frame_id) OVERRIDE;
+
+  // Overridden from content::NotificationObserver:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+ private:
+  // Enum of the load states for the NTP.
+  //
+  // Once the user loads the NTP the |ntp_load_state_| changes to
+  // WAITING_FOR_FRAME_ID and the chrome::search::mode::Type changes to
+  // MODE_NTP_LOADING. The |ntp_load_state_| progresses through the remaining
+  // states and when done chrome::search::mode::Type is changed to MODE_NTP.
+  //
+  // This code is intended to avoid a flash between white (default background
+  // color) and the background the pages wants (gray). We know the CSS has been
+  // applied once we get DocumentLoadedInFrame() and we know the backing store
+  // has been updated once we get a paint.
+  enum NTPLoadState {
+    // The default initial state.
+    DEFAULT,
+
+    // The user loaded the NTP and we're waiting for the id of the main frame.
+    WAITING_FOR_FRAME_ID,
+
+    // We got the frame id (in |main_frame_id_|) and are waiting for the frame
+    // to complete loading.
+    WAITING_FOR_FRAME_LOAD,
+
+    // The document finished loading. We're now waiting for a paint.
+    WAITING_FOR_PAINT,
+  };
+
+  // Returns the current RenderWidgetHost of the |web_contents()|.
+  content::RenderWidgetHost* GetRenderWidgetHost();
+
+  const bool is_search_enabled_;
+
+  // Model object for UI that cares about search state.
+  scoped_ptr<SearchModel> model_;
+
+  content::NotificationRegistrar registrar_;
+
+  // See description above NTPLoadState.
+  NTPLoadState ntp_load_state_;
+
+  // See description above NTPLoadState.
+  int64 main_frame_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(SearchTabHelper);
+};
+
+}  // namespace search
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_SEARCH_SEARCH_TAB_HELPER_H_