Remove touch_drag_drop web preference. It was added in r184242 for tests to be

webkit/glue/webpreferences.cc

Index: webkit/glue/webpreferences.cc
diff --git a/webkit/glue/webpreferences.cc b/webkit/glue/webpreferences.cc
index 98c90fd62e670c734f6b1d2f92be4043ae684979..6baee6337e631bcb05b26cca1f81bcf79fd080cc 100644
--- a/webkit/glue/webpreferences.cc
+++ b/webkit/glue/webpreferences.cc
@@ -105,7 +105,6 @@ WebPreferences::WebPreferences()
       device_supports_touch(false),
       device_supports_mouse(true),
       touch_adjustment_enabled(true),
-      touch_drag_drop_enabled(false),
       fixed_position_creates_stacking_context(false),
       sync_xhr_in_documents_enabled(true),
       deferred_image_decoding_enabled(false),
@@ -446,7 +445,6 @@ void ApplyWebPreferences(const WebPreferences& prefs, WebView* web_view) {
   settings->setDeviceSupportsTouch(prefs.device_supports_touch);
   settings->setDeviceSupportsMouse(prefs.device_supports_mouse);
   settings->setEnableTouchAdjustment(prefs.touch_adjustment_enabled);
-  settings->setTouchDragDropEnabled(prefs.touch_drag_drop_enabled);
 
   settings->setFixedPositionCreatesStackingContext(
       prefs.fixed_position_creates_stacking_context);