NTP: Fix metrics recording crash by plumbing the necessary data to Java.

components/ntp_tiles/most_visited_sites.h

Index: components/ntp_tiles/most_visited_sites.h
diff --git a/components/ntp_tiles/most_visited_sites.h b/components/ntp_tiles/most_visited_sites.h
index 429be26fb2d7f4d4e2cad66077777a02a9551906..3b1755e913160c3930914055d0827fc694ad90e0 100644
--- a/components/ntp_tiles/most_visited_sites.h
+++ b/components/ntp_tiles/most_visited_sites.h
@@ -95,8 +95,38 @@ class MostVisitedSites : public history::TopSitesObserver,
   using SuggestionsVector = std::vector<Suggestion>;
   using PopularSitesVector = std::vector<PopularSites::Site>;
 
+  // The visual type of a most visited tile.
+  //
+  // These values must stay in sync with the MostVisitedTileType enum
+  // in histograms.xml.
+  //
+  // A Java counterpart will be generated for this enum.
+  // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.ntp
+  enum MostVisitedTileType {
+    // The icon or thumbnail hasn't loaded yet.
+    NONE,
+    // The item displays a site's actual favicon or touch icon.
+    ICON_REAL,
+    // The item displays a color derived from the site's favicon or touch icon.
+    ICON_COLOR,
+    // The item displays a default gray box in place of an icon.
+    ICON_DEFAULT,
+    NUM_TILE_TYPES,
+  };

[Marc Treib, 2016/06/29 08:19:32]

Any particular reason for moving this into the header?

[dewittj, 2016/06/30 17:48:54]

A few reasons.  This enum is exposed to Java, making it semi-public already. 
Also, the gypi build file appears to take only one source file, so I preferred
to have it scan the .h than to make two rules, one for the .h and one for the
.cc

[Marc Treib, 2016/07/01 10:01:03]

Acknowledged.

+
   // The source of the Most Visited sites.
-  enum MostVisitedSource { TOP_SITES, SUGGESTIONS_SERVICE, POPULAR, WHITELIST };
+  // A Java counterpart will be generated for this enum.
+  // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.ntp
+  enum MostVisitedSource {
+    // Item comes from the regional top sites list.

[Marc Treib, 2016/06/29 08:19:32]

Nope, these are the *personal* top sites.

[Bernhard Bauer, 2016/06/29 10:17:43]

(The regional ones are called "popular sites" 😃)

[dewittj, 2016/06/30 17:48:54]

Done.

+    TOP_SITES,
+    // Item comes from the suggestions service.
+    SUGGESTIONS_SERVICE,
+    // Item is most popular.

[Marc Treib, 2016/06/29 08:19:32]

These are the regionally popular ones.

[dewittj, 2016/06/30 17:48:54]

Done.

+    POPULAR,
+    // Item on static whitelist

[Marc Treib, 2016/06/29 08:19:32]

s/static/supervised user/ ?
(These whitelists exist only for supervised users, and I don't know what
"static" is supposed to mean)

[dewittj, 2016/06/30 17:48:54]

Done.

+    WHITELIST
+  };
 
   // The observer to be notified when the list of most visited sites changes.
   class Observer {
@@ -149,7 +179,6 @@ class MostVisitedSites : public history::TopSitesObserver,
   using ThumbnailCallback = base::Callback<
       void(bool /* is_local_thumbnail */, const SkBitmap* /* bitmap */)>;
   void AddOrRemoveBlacklistedUrl(const GURL& url, bool add_url);
-  void RecordTileTypeMetrics(const std::vector<int>& tile_types);
   void RecordOpenedMostVisitedItem(int index, int tile_type);
 
   // MostVisitedSitesSupervisor::Observer implementation.