Add UMA stats for which icon types are shown and clicked on the NTP.

chrome/browser/android/most_visited_sites.h

Index: chrome/browser/android/most_visited_sites.h
diff --git a/chrome/browser/android/most_visited_sites.h b/chrome/browser/android/most_visited_sites.h
index 0a20c7c154253610f2b80a8995c2d05a013c4024..18eba7ab34500ba90e339c30f5bb43e5b0c5ae40 100644
--- a/chrome/browser/android/most_visited_sites.h
+++ b/chrome/browser/android/most_visited_sites.h
@@ -38,7 +38,6 @@ class MostVisitedSites : public sync_driver::SyncServiceObserver,
  public:
   explicit MostVisitedSites(Profile* profile);
   void Destroy(JNIEnv* env, jobject obj);
-  void OnLoadingComplete(JNIEnv* env, jobject obj);
   void SetMostVisitedURLsObserver(JNIEnv* env,
                                   jobject obj,
                                   jobject j_observer,
@@ -49,7 +48,14 @@ class MostVisitedSites : public sync_driver::SyncServiceObserver,
                        jobject j_callback);
 
   void BlacklistUrl(JNIEnv* env, jobject obj, jstring j_url);
-  void RecordOpenedMostVisitedItem(JNIEnv* env, jobject obj, jint index);
+  void RecordTileTypeMetrics(JNIEnv* env,
+                             jobject obj,
+                             jintArray jtile_types,
+                             jboolean is_icon_mode);
+  void RecordOpenedMostVisitedItem(JNIEnv* env,
+                                   jobject obj,
+                                   jint index,
+                                   jint tile_type);
 
   // sync_driver::SyncServiceObserver implementation.
   void OnStateChanged() override;
@@ -195,16 +201,6 @@ class MostVisitedSites : public sync_driver::SyncServiceObserver,
   // recorded once both the previous flags are true.
   bool recorded_uma_;
 
-  // Counters for UMA metrics.
-
-  // Number of tiles using a local thumbnail image for this NTP session.
-  int num_local_thumbs_;

[newt (away), 2015/09/28 22:34:21]

These counts are no longer needed, since RecordTileTypeMetrics() gets a list of
tile types from Java.

-  // Number of tiles for which a server thumbnail is provided.
-  int num_server_thumbs_;
-  // Number of tiles for which no thumbnail is found/specified.
-  // In this case a gray tile is used as the main tile.
-  int num_empty_thumbs_;
-
   ScopedObserver<history::TopSites, history::TopSitesObserver> scoped_observer_;
 
   MostVisitedSource mv_source_;