Add disabled origin trial feature list

content/public/common/content_client.h

Index: content/public/common/content_client.h
diff --git a/content/public/common/content_client.h b/content/public/common/content_client.h
index 5510cb27f9145e769ea02cf7df17502e72cafe1a..fa93cdcc713d76ecea30a69b6e5fbc4740e36613 100644
--- a/content/public/common/content_client.h
+++ b/content/public/common/content_client.h
@@ -175,7 +175,11 @@ class CONTENT_EXPORT ContentClient {
 
   // Returns the public key to be used for origin trials, or an empty string if
   // origin trials are not enabled in this context.
-  virtual base::StringPiece GetOriginTrialPublicKey();
+  virtual base::StringPiece GetOriginTrialPublicKey() const;
+
+  // Returns true if the named experimental feature should be disabled in origin
+  // trials, even if a valid token is present.
+  virtual bool IsOriginTrialFeatureDisabled(base::StringPiece feature) const;
 
 #if defined(OS_ANDROID)
   // Returns true for clients like Android WebView that uses synchronous