UMA counts for corrupt cache db.

chrome/browser/chromeos/gdata/drive_cache_metadata.cc

Index: chrome/browser/chromeos/gdata/drive_cache_metadata.cc
===================================================================
--- chrome/browser/chromeos/gdata/drive_cache_metadata.cc	(revision 158657)
+++ chrome/browser/chromeos/gdata/drive_cache_metadata.cc	(working copy)
@@ -8,6 +8,7 @@
 
 #include "base/callback.h"
 #include "base/file_util.h"
+#include "base/metrics/histogram.h"
 #include "base/sequenced_task_runner.h"
 #include "chrome/browser/chromeos/gdata/drive.pb.h"
 #include "chrome/browser/chromeos/gdata/drive_file_system_util.h"
@@ -16,6 +17,13 @@
 
 namespace {
 
+enum DBOpenStatus {
+  DB_OPEN_SUCCESS,
+  DB_OPEN_FAILURE_CORRUPTION,
+  DB_OPEN_FAILURE_OTHER,
+  DB_OPEN_MAX_VALUE,
+};
+
 // A map table of resource ID to file path.
 typedef std::map<std::string, FilePath> ResourceIdToFilePathMap;
 
@@ -466,8 +474,11 @@
 
   // Delete the db and scan the physical cache. This will fix a corrupt db, but
   // perhaps not other causes of failed DB::Open.
+  DBOpenStatus uma_status = DB_OPEN_SUCCESS;
   if (!db_status.ok()) {
-    DVLOG(1) << "Detected corrupt db";
+    LOG(WARNING) << "Cache db failed to open: " << db_status.ToString();
+    uma_status = db_status.IsCorruption() ?
+                 DB_OPEN_FAILURE_CORRUPTION : DB_OPEN_FAILURE_OTHER;
     const bool deleted = file_util::Delete(db_path, true);
     DCHECK(deleted);
     db_status = leveldb::DB::Open(options, db_path.value(), &level_db);
@@ -479,6 +490,9 @@
   DCHECK(level_db);
   level_db_.reset(level_db);
 
+  UMA_HISTOGRAM_ENUMERATION(
+      "Drive.CacheDBOpenStatus", uma_status, DB_OPEN_MAX_VALUE);
+
   // We scan the cache directories to initialize the cache database if we
   // were previously using the cache map.
   if (scan_cache) {