Do not clear document background in Android WebView

android_webview/native/aw_settings.cc

 // 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.
 
 #include "android_webview/native/aw_settings.h"
 
 #include "android_webview/browser/renderer_host/aw_render_view_host_ext.h"
 #include "android_webview/native/aw_contents.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
@@ skipping 159 matching lines @@
   UpdateEverything();
 }
 
 void AwSettings::WebContentsDestroyed(content::WebContents* web_contents) {
   delete this;
 }
 
 // static
 void AwSettings::PopulateFixedPreferences(WebPreferences* web_prefs) {
   web_prefs->shrinks_standalone_images_to_fit = false;
+  web_prefs->should_clear_document_background = false;
 }
 
 void AwSettings::PopulateWebPreferences(WebPreferences* web_prefs) {
   JNIEnv* env = base::android::AttachCurrentThread();
   CHECK(env);
 
   AwRenderViewHostExt* render_view_host_ext = GetAwRenderViewHostExt();
   if (!render_view_host_ext) return;
 
   ScopedJavaLocalRef<jobject> scoped_obj = aw_settings_.get(env);
@@ skipping 133 matching lines @@
 static jstring GetDefaultUserAgent(JNIEnv* env, jclass clazz) {
   return base::android::ConvertUTF8ToJavaString(
       env, content::GetUserAgent(GURL())).Release();
 }
 
 bool RegisterAwSettings(JNIEnv* env) {
   return RegisterNativesImpl(env) >= 0;
 }
 
 }  // namespace android_webview