Allow Web Animations CSS flag to be turned off as well as on

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 14dfc5a565890a7a0291be823994cf5e1244b636..6d36600d3e0c3386d2db5c0ede53bcdfa66bd27e 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -306,15 +306,18 @@ const char kDisableThreadedHTMLParser[]     = "disable-threaded-html-parser";
 const char kDisableUniversalAcceleratedOverflowScroll[] =
     "disable-universal-accelerated-overflow-scroll";
 
+// Disables unprefixed Media Source API (i.e., the MediaSource object).
+const char kDisableUnprefixedMediaSource[]  = "disable-unprefixed-media-source";
+
+// Disable CSS Transitions / Animations on the Web Animations model.
+const char kDisableWebAnimationsCSS[]        = "disable-web-animations-css";
+
 // Disable web audio API.
 const char kDisableWebAudio[]               = "disable-webaudio";
 
 // Disables prefixed Media Source API (i.e., the WebKitMediaSource object).
 const char kDisableWebKitMediaSource[]      = "disable-webkit-media-source";
 
-// Disables unprefixed Media Source API (i.e., the MediaSource object).
-const char kDisableUnprefixedMediaSource[]  = "disable-unprefixed-media-source";
-
 // Don't enforce the same-origin policy. (Used by people testing their sites.)
 const char kDisableWebSecurity[]            = "disable-web-security";