Resize only the virtual viewport when the OSK triggers a resize.

chrome/android/java/src/org/chromium/chrome/browser/ChromeSwitches.java

 // Copyright 2014 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.
 
 package org.chromium.chrome.browser;
 
 /**
  * Contains all of the command line switches that are specific to the chrome/
  * portion of Chromium on Android.
  */
@@ skipping 186 matching lines @@
     public static final String DISABLE_OFFLINE_PAGES = "disable-offline-pages";
 
     /**
      * Enable keyboard accessory view that shows autofill suggestions on top of the keyboard.
      * Native switch - autofill::switches::kEnableAccessorySuggestionView
      */
     public static final String ENABLE_AUTOFILL_KEYBOARD_ACCESSORY =
             "enable-autofill-keyboard-accessory-view";
 
     /**
+     * Enables overscroll of the on screen keyboard. With this flag on, the OSK will only resize the
+     * visual viewport.
+     * Native switch - switches::kEnableOSKOverscroll
+     */
+    public static final String ENABLE_OSK_OVERSCROLL = "enable-osk-overscroll";
+
+    /**
      * Enables hung renderer InfoBar activation for unresponsive web content.
      * Native switch - switches::kEnableHungRendererInfoBar
      */
     public static final String ENABLE_HUNG_RENDERER_INFOBAR = "enable-hung-renderer-infobar";
 
     /**
      * Enables Web Notification custom layouts.
      * Native switch - switches::kEnableWebNotificationCustomLayouts
      */
     public static final String ENABLE_WEB_NOTIFICATION_CUSTOM_LAYOUTS =
@@ skipping 27 matching lines @@
 
     /**
      * Enable tab switcher in document mode (merged tabs and apps option).
      */
     public static final String ENABLE_TAB_SWITCHER_IN_DOCUMENT_MODE =
             "enable-tab-switcher-in-document-mode";
 
     // Prevent instantiation.
     private ChromeSwitches() {}
 }