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

chrome/browser/chrome_content_browser_client.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 "chrome/browser/chrome_content_browser_client.h"
 
 #include <map>
 #include <set>
 #include <utility>
 #include <vector>
@@ skipping 638 matching lines @@
     return kMaxFSM;
 
   // The font scale multiplier varies linearly between kMinFSM and kMaxFSM.
   float ratio = static_cast<float>(minWidth - kWidthForMinFSM) /
       (kWidthForMaxFSM - kWidthForMinFSM);
   return ratio * (kMaxFSM - kMinFSM) + kMinFSM;
 }
 #endif  // defined(OS_ANDROID)
 
 #if defined(ENABLE_EXTENSIONS)
 // By default, JavaScript and images are enabled in guest content.

[Bernhard Bauer, 2016/04/20 16:08:53]

Update the comment.

[mlamouri (slow - plz ping), 2016/04/20 18:36:47]

Done.

 void GetGuestViewDefaultContentSettingRules(
     bool incognito,
     RendererContentSettingRules* rules) {
   rules->image_rules.push_back(
       ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
                                   ContentSettingsPattern::Wildcard(),
                                   CONTENT_SETTING_ALLOW,
                                   std::string(),
                                   incognito));
 
   rules->script_rules.push_back(
       ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
                                   ContentSettingsPattern::Wildcard(),
                                   CONTENT_SETTING_ALLOW,
                                   std::string(),
                                   incognito));
+  rules->autoplay_rules.push_back(
+      ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
+                                  ContentSettingsPattern::Wildcard(),
+                                  CONTENT_SETTING_ALLOW,
+                                  std::string(),
+                                  incognito));
 }
 #endif  // defined(ENABLE_EXTENSIONS)
 
 void CreateUsbDeviceManager(
     RenderFrameHost* render_frame_host,
     mojo::InterfaceRequest<device::usb::DeviceManager> request) {
   WebContents* web_contents =
       WebContents::FromRenderFrameHost(render_frame_host);
   if (!web_contents) {
     NOTREACHED();
@@ skipping 2274 matching lines @@
   if (channel <= kMaxDisableEncryptionChannel) {
     static const char* const kWebRtcDevSwitchNames[] = {
       switches::kDisableWebRtcEncryption,
     };
     to_command_line->CopySwitchesFrom(from_command_line,
                                       kWebRtcDevSwitchNames,
                                       arraysize(kWebRtcDevSwitchNames));
   }
 }
 #endif  // defined(ENABLE_WEBRTC)