Add 'autoplay' content settings and expose it to Blink.

components/content_settings/core/common/content_settings.cc

 // Copyright (c) 2011 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 "components/content_settings/core/common/content_settings.h"
 
 #include "base/containers/hash_tables.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/stl_util.h"
@@ skipping 37 matching lines @@
     CONTENT_SETTINGS_TYPE_PROTECTED_MEDIA_IDENTIFIER,
 #else
     CONTENT_SETTINGS_TYPE_DEFAULT,  // PROTECTED_MEDIA_IDENTIFIER (mobile only).
 #endif
     CONTENT_SETTINGS_TYPE_APP_BANNER,
     CONTENT_SETTINGS_TYPE_SITE_ENGAGEMENT,
     CONTENT_SETTINGS_TYPE_DURABLE_STORAGE,
     CONTENT_SETTINGS_TYPE_KEYGEN,
     CONTENT_SETTINGS_TYPE_BLUETOOTH_GUARD,
     CONTENT_SETTINGS_TYPE_BACKGROUND_SYNC,
+    CONTENT_SETTINGS_TYPE_AUTOPLAY,
 };
 
 int ContentSettingTypeToHistogramValue(ContentSettingsType content_setting,
                                        size_t* num_values) {
   // Translate the list above into a map for fast lookup.
   typedef base::hash_map<int, int> Map;
   CR_DEFINE_STATIC_LOCAL(Map, kMap, ());
   if (kMap.empty()) {
     for (size_t i = 0; i < arraysize(kHistogramOrder); ++i) {
       if (kHistogramOrder[i] != CONTENT_SETTINGS_TYPE_DEFAULT)
@@ skipping 21 matching lines @@
 ContentSettingPatternSource::ContentSettingPatternSource()
     : setting(CONTENT_SETTING_DEFAULT), incognito(false) {
 }
 
 ContentSettingPatternSource::ContentSettingPatternSource(
     const ContentSettingPatternSource& other) = default;
 
 RendererContentSettingRules::RendererContentSettingRules() {}
 
 RendererContentSettingRules::~RendererContentSettingRules() {}