Add SoundContentSetting to about_flags. Also add Sound to site_details
page.

Bug: 743001
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I43092e0bc7861d62c87851e2c15f127ca3f49a18
Reviewed-on: https://chromium-review.googlesource.com/633464
Reviewed-by: Tommy Li <[email protected]>
Reviewed-by: Mounir Lamouri <[email protected]>
Reviewed-by: Yuri Wiitala <[email protected]>
Commit-Queue: Tommy Steimel <[email protected]>
Cr-Commit-Position: refs/heads/master@{#497897}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 75473acb..c7b9b27b 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -729,6 +729,9 @@
 extern const char kSoftwareRasterizerName[];
 extern const char kSoftwareRasterizerDescription[];
 
+extern const char kSoundContentSettingName[];
+extern const char kSoundContentSettingDescription[];
+
 extern const char kSpeculativePrefetchName[];
 extern const char kSpeculativePrefetchDescription[];