[Android WebView] make spellcheck off by default and opt-in using spellcheck="true" attribute.

content/public/common/web_preferences.cc

 // Copyright 2014 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/common/web_preferences.h"
 
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
@@ skipping 188 matching lines @@
       viewport_meta_layout_size_quirk(false),
       viewport_meta_merge_content_quirk(false),
       viewport_meta_non_user_scalable_quirk(false),
       viewport_meta_zero_values_quirk(false),
       clobber_user_agent_initial_scale_quirk(false),
       ignore_main_frame_overflow_hidden_quirk(false),
       report_screen_size_in_physical_pixels_quirk(false),
       resue_global_for_unowned_main_frame(false),
       autoplay_muted_videos_enabled(false),
       progress_bar_completion(ProgressBarCompletion::LOAD_EVENT),
+      spellcheck_enabled_by_default(true),
 #endif
 #if defined(OS_ANDROID)
       default_minimum_page_scale_factor(0.25f),
       default_maximum_page_scale_factor(5.f)
 #elif defined(OS_MACOSX)
       default_minimum_page_scale_factor(1.f),
       default_maximum_page_scale_factor(3.f)
 #else
       default_minimum_page_scale_factor(1.f),
       default_maximum_page_scale_factor(4.f)
 #endif
 {
   standard_font_family_map[kCommonScript] =
       base::ASCIIToUTF16("Times New Roman");
   fixed_font_family_map[kCommonScript] = base::ASCIIToUTF16("Courier New");
   serif_font_family_map[kCommonScript] = base::ASCIIToUTF16("Times New Roman");
   sans_serif_font_family_map[kCommonScript] = base::ASCIIToUTF16("Arial");
   cursive_font_family_map[kCommonScript] = base::ASCIIToUTF16("Script");
   fantasy_font_family_map[kCommonScript] = base::ASCIIToUTF16("Impact");
   pictograph_font_family_map[kCommonScript] =
       base::ASCIIToUTF16("Times New Roman");
 }
 
 WebPreferences::WebPreferences(const WebPreferences& other) = default;
 
 WebPreferences::~WebPreferences() {
 }
 
 }  // namespace content