Disable custom scrollbar in main frame for Android

webkit/glue/webpreferences.cc

 // 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.
 
 #include "webkit/glue/webpreferences.h"
 
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebNetworkStateNotifier.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebRuntimeFeatures.h"
@@ skipping 419 matching lines @@
 
   settings->setFixedPositionCreatesStackingContext(
       fixed_position_creates_stacking_context);
 
   settings->setApplyPageScaleFactorInCompositor(
       apply_page_scale_factor_in_compositor);
 
   settings->setDeferredImageDecodingEnabled(deferred_image_decoding_enabled);
 
 #if defined(OS_ANDROID)
+  settings->setAllowCustomScrollbarInMainFrame(false);
   settings->setTextAutosizingEnabled(text_autosizing_enabled);
   settings->setTextAutosizingFontScaleFactor(font_scale_factor);
   web_view->setIgnoreViewportTagMaximumScale(force_enable_zoom);
   settings->setAutoZoomFocusedNodeToLegibleScale(true);
   settings->setDoubleTapToZoomEnabled(true);
   settings->setMediaPlaybackRequiresUserGesture(
       user_gesture_required_for_media_playback);
   settings->setSupportsMultipleWindows(supports_multiple_windows);
 #endif
 
   WebNetworkStateNotifier::setOnLine(is_online);
 }
 
 }  // namespace webkit_glue