Add options for audio/video autoplay to chrome://settings/content.

chrome/renderer/content_settings_observer.cc

Index: chrome/renderer/content_settings_observer.cc
diff --git a/chrome/renderer/content_settings_observer.cc b/chrome/renderer/content_settings_observer.cc
index 9707f3da239b05b11b95e9d85dc4484cfe02da59..e88abe287df0b84e04818d1c89ec1cc4fafde2e1 100644
--- a/chrome/renderer/content_settings_observer.cc
+++ b/chrome/renderer/content_settings_observer.cc
@@ -349,6 +349,19 @@ bool ContentSettingsObserver::allowIndexedDB(const WebString& name,
   return result;
 }
 
+bool ContentSettingsObserver::allowMediaAutoplay(bool hidden) {
+  if (!content_setting_rules_)
+    return true;
+
+  WebFrame* frame = render_frame()->GetWebFrame();
+  const ContentSetting setting = GetContentSettingFromRules(
+      content_setting_rules_->media_autoplay_rules, frame,
+      GURL(frame->document().securityOrigin().toString()));
+
+  return setting == CONTENT_SETTING_ALLOW ||
+         (setting == CONTENT_SETTING_DETECT_IMPORTANT_CONTENT && !hidden);

[philipj_slow, 2015/10/23 12:17:30]

Oh... so "important content" actually means anything in an open tab?

[DaleCurtis, 2015/10/23 19:21:27]

Currently and as planned yes. There are discussion to see if the plugin power
saver heuristics could be used: 

https://code.google.com/p/chromium/codesearch#chromium/src/content/renderer/p...

+}
+
 bool ContentSettingsObserver::allowPlugins(bool enabled_per_settings) {
   return enabled_per_settings;
 }