ntp4: make app-install-via-drag less janky

chrome/browser/extensions/extension_prefs.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_EXTENSIONS_EXTENSION_PREFS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 85 matching lines @@
 
   // Get the order that the browser actions appear in the toolbar.
   std::vector<std::string> GetToolbarOrder();
 
   // Set the order that the browser actions appear in the toolbar.
   void SetToolbarOrder(const std::vector<std::string>& extension_ids);
 
   // Called when an extension is installed, so that prefs get created.
   void OnExtensionInstalled(const Extension* extension,
                             Extension::State initial_state,
-                            bool from_webstore);
+                            bool from_webstore,
+                            int page_index);
 
   // Called when an extension is uninstalled, so that prefs get cleaned up.
   void OnExtensionUninstalled(const std::string& extension_id,
                               const Extension::Location& location,
                               bool external_uninstall);
 
   // Called to change the extension's state when it is enabled/disabled.
   void SetExtensionState(const std::string& extension_id, Extension::State);
 
   // Returns all installed extensions
@@ skipping 149 matching lines @@
   // Get the application launch index for an extension with |extension_id|. This
   // determines the order of which the applications appear on the New Tab Page.
   // A value of 0 generally indicates top left. If the extension has no launch
   // index a -1 value is returned.
   int GetAppLaunchIndex(const std::string& extension_id);
 
   // Sets a specific launch index for an extension with |extension_id|.
   void SetAppLaunchIndex(const std::string& extension_id, int index);
 
   // Gets the next available application launch index. This is 1 higher than the
-  // highest current application launch index found.
-  int GetNextAppLaunchIndex();
+  // highest current application launch index found for the page |on_page|.
+  int GetNextAppLaunchIndex(int on_page);
 
   // Sets the order the apps should be displayed in the app launcher.
   void SetAppLauncherOrder(const std::vector<std::string>& extension_ids);
 
   // Get the application page index for an extension with |extension_id|.  This
   // determines which page an app will appear on in page-based NTPs.  If
   // the app has no page specified, -1 is returned.
   int GetPageIndex(const std::string& extension_id);
 
   // Sets a specific page index for an extension with |extension_id|.
@@ skipping 192 matching lines @@
 
   scoped_refptr<ExtensionContentSettingsStore> content_settings_store_;
 
   // The URLs of all of the toolstrips.
   URLList shelf_order_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_