Do not clear document background in Android WebView

content/renderer/web_preferences.cc

 // Copyright 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.
 
 #include "content/public/renderer/web_preferences.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 #include "third_party/WebKit/public/web/WebKit.h"
@@ skipping 270 matching lines @@
   // ChromeClient::tabsToLinks which is part of the glue code.
   web_view->setTabsToLinks(prefs.tabs_to_links);
 
   settings->setFullScreenEnabled(prefs.fullscreen_enabled);
   settings->setAllowDisplayOfInsecureContent(
       prefs.allow_displaying_insecure_content);
   settings->setAllowRunningOfInsecureContent(
       prefs.allow_running_insecure_content);
   settings->setPasswordEchoEnabled(prefs.password_echo_enabled);
   settings->setShouldPrintBackgrounds(prefs.should_print_backgrounds);
+  settings->setShouldClearDocumentBackground(
+      prefs.should_clear_document_background);
   settings->setEnableScrollAnimator(prefs.enable_scroll_animator);
   settings->setVisualWordMovementEnabled(prefs.visual_word_movement_enabled);
 
   settings->setRegionBasedColumnsEnabled(prefs.region_based_columns_enabled);
 
   WebRuntimeFeatures::enableLazyLayout(prefs.lazy_layout_enabled);
   WebRuntimeFeatures::enableTouch(prefs.touch_enabled);
   settings->setMaxTouchPoints(prefs.pointer_events_max_touch_points);
   settings->setDeviceSupportsTouch(prefs.device_supports_touch);
   settings->setDeviceSupportsMouse(prefs.device_supports_mouse);
@@ skipping 69 matching lines @@
   settings->setPinchVirtualViewportEnabled(
       prefs.pinch_virtual_viewport_enabled);
 
   settings->setPinchOverlayScrollbarThickness(
       prefs.pinch_overlay_scrollbar_thickness);
   settings->setUseSolidColorScrollbars(prefs.use_solid_color_scrollbars);
   settings->setCompositorTouchHitTesting(prefs.compositor_touch_hit_testing);
 }
 
 }  // namespace content