Cleanup: Change LogMostVisitedImpression|Navigation APIs to take an enum

chrome/common/ntp_logging_events.h

Index: chrome/common/ntp_logging_events.h
diff --git a/chrome/common/ntp_logging_events.h b/chrome/common/ntp_logging_events.h
index be1bfeef6358ab75c2b94edd9b4cbed86ddf11fe..cec183415a84dfa6664a7606dd5abdbf59107d05 100644
--- a/chrome/common/ntp_logging_events.h
+++ b/chrome/common/ntp_logging_events.h
@@ -49,4 +49,14 @@ enum NTPLoggingEventType {
   NTP_EVENT_TYPE_LAST = NTP_TILE_LOADED
 };
 
+// The source of an NTP tile.
+// Note: Keep in sync with browser/resources/local_ntp/most_visited_util.js and
+// browser/resources/local_ntp/most_visited_single.js.
+// TODO(treib): Merge this into MostVisitedSource from components/ntp_tiles.
+enum NTPLoggingTileSource {

[dcheng, 2016/07/06 01:51:25]

Nit: Can we make this a scoped enum, i.e. enum class NTPLoggingTileSource? Then
the enum members can just be CLIENT, SERVER, LAST.

[Marc Treib, 2016/07/06 08:49:06]

The enum values are duplicated in JavaScript code. To at least make them
greppable, I'd like to keep the long, unique names.
(If you know of a way to share an enum (or just some constants) between C++ and
JS, I'd love to hear it...)

[Bernhard Bauer, 2016/07/06 09:00:51]

BUT I WANTED TO USE THE SHORT VALUES IN JAVASCRIPT AS WELL 😉

If we always use them namespaced (which we have to do anyway), grepping should
be possible too, no? You'd just have to use different namespace separators for
JS vs C++.

[Marc Treib, 2016/07/06 10:14:38]

Which is still a lot less convenient (and thus more error-prone) than just
searching for one string. But okay, I guess I'm outvoted here. Done.

+  NTP_TILE_SOURCE_CLIENT = 0,
+  NTP_TILE_SOURCE_SERVER = 1,
+  NTP_TILE_SOURCE_LAST = NTP_TILE_SOURCE_SERVER
+};
+
 #endif  // CHROME_COMMON_NTP_LOGGING_EVENTS_H_