[content shell] enable touch events for layout tests

webkit/glue/webpreferences.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.
 //
 // A struct for managing webkit's settings.
 //
 // Adding new values to this class probably involves updating
 // WebKit::WebSettings, content/common/view_messages.h, browser/tab_contents/
 // render_view_host_delegate_helper.cc, and browser/profiles/profile.cc.
 
@@ skipping 127 matching lines @@
   bool enable_scroll_animator;
   bool visual_word_movement_enabled;
   bool css_sticky_position_enabled;
   bool css_shaders_enabled;
   bool css_variables_enabled;
   bool css_grid_layout_enabled;
   bool touch_enabled;
   bool device_supports_touch;
   bool device_supports_mouse;
   bool touch_adjustment_enabled;
+  bool touch_drag_drop_enabled;
   int default_tile_width;
   int default_tile_height;
   int max_untiled_layer_width;
   int max_untiled_layer_height;
   bool fixed_position_creates_stacking_context;
   bool sync_xhr_in_documents_enabled;
   bool deferred_image_decoding_enabled;
   bool should_respect_image_orientation;
   int number_of_cpu_cores;
   EditingBehavior editing_behavior;
@@ skipping 20 matching lines @@
   // the embedder to use the same default value.
   WebPreferences();
   ~WebPreferences();
 
   void Apply(WebKit::WebView* web_view) const;
 };
 
 }  // namespace webkit_glue
 
 #endif  // WEBKIT_GLUE_WEBPREFERENCES_H__