Drop ntp_snippets::kStudyName in chrome://flags

components/ntp_snippets/ntp_snippets_constants.h

Index: components/ntp_snippets/ntp_snippets_constants.h
diff --git a/components/ntp_snippets/ntp_snippets_constants.h b/components/ntp_snippets/ntp_snippets_constants.h
index 2c17eb0591a009780e89ebfde114732a077d1d38..aff5c3720d49b5a74cceb8e3c449a17aced75d51 100644
--- a/components/ntp_snippets/ntp_snippets_constants.h
+++ b/components/ntp_snippets/ntp_snippets_constants.h
@@ -9,9 +9,6 @@
 
 namespace ntp_snippets {
 
-// Name of the variation parameters study to configure NTP snippets.
-extern const char kStudyName[];
-
 // Name of the folder where the snippets database should be stored. This is only
 // the name of the folder, not a full path - it must be appended to e.g. the
 // profile path.