Add a --enable-gesture-typing flag. Currently this flag does nothing.

ui/keyboard/keyboard_switches.h

 // Copyright (c) 2013 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 UI_KEYBOARD_KEYBOARD_SWITCHES_H_
 #define UI_KEYBOARD_KEYBOARD_SWITCHES_H_
 
 #include "ui/keyboard/keyboard_export.h"
 
 namespace keyboard {
 namespace switches {
 
 // Enables the swipe selection feature on the virtual keyboard.
 KEYBOARD_EXPORT extern const char kEnableSwipeSelection[];
 
 // Disables IME extension APIs from overriding the URL for specifying the
 // contents of the virtual keyboard container.
 KEYBOARD_EXPORT extern const char kDisableInputView[];
 
 // Enables an IME extension API to set a URL for specifying the contents
 // of the virtual keyboard container.
 KEYBOARD_EXPORT extern const char kEnableInputView[];
 
 // Enables experimental features for IME extensions.
 KEYBOARD_EXPORT extern const char kEnableExperimentalInputViewFeatures[];
 
+// Enables gesture typing for the virtual keyboard.
+KEYBOARD_EXPORT extern const char kEnableGestureTyping[];
+
 // Enables the virtual keyboard.
 KEYBOARD_EXPORT extern const char kEnableVirtualKeyboard[];
 
 // Disabled overscrolling of web content when the virtual keyboard is displayed.
 // If disabled, the work area is resized to restrict windows from overlapping
 // with the keybaord area.
 KEYBOARD_EXPORT extern const char kDisableVirtualKeyboardOverscroll[];
 
 // Enable overscrolling of web content when the virtual keyboard is displayed
 // to provide access to content that would otherwise be occluded.
 KEYBOARD_EXPORT extern const char kEnableVirtualKeyboardOverscroll[];
 
 // Disable automatic showing/hiding of the keyboard based on the devices plugged
 // in.
 KEYBOARD_EXPORT extern const char kDisableSmartVirtualKeyboard[];
 
 }  // namespace switches
 }  // namespace keyboard
 
 #endif  //  UI_KEYBOARD_KEYBOARD_SWITCHES_H_