Drop diagnostics reference to out-dated database.

chrome/browser/diagnostics/diagnostics_metrics.cc

Index: chrome/browser/diagnostics/diagnostics_metrics.cc
diff --git a/chrome/browser/diagnostics/diagnostics_metrics.cc b/chrome/browser/diagnostics/diagnostics_metrics.cc
index 004f4c5e36211abb85e83a6a7ab2cc7ece8f71f8..2c5a646a1652b202a35018a18ce075a5bf7baea7 100644
--- a/chrome/browser/diagnostics/diagnostics_metrics.cc
+++ b/chrome/browser/diagnostics/diagnostics_metrics.cc
@@ -48,8 +48,9 @@ const TestNameInfo kTestNameInfo[] = {
     {"SQLiteIntegrityHistory", "History database"},
     {"SQLiteIntegrityNSSCert", "NSS certificate database"},
     {"SQLiteIntegrityNSSKey", "NSS Key database"},
-    {"SQLiteIntegrityThumbnails", "Thumbnails database"},
+    {"SQLiteIntegrityFavicons", "Favicons database"},
     {"SQLiteIntegrityWebData", "Web Data database"},
+    {"SQLiteIntegrityTopSites", "Top Sites database"},

[Scott Hess - ex-Googler, 2016/06/03 21:15:31]

I could see an argument for leaving the THUMBNAILS case in place, and adding new
FAVICONS case, because THUMBNAILS has been generating bad data.  This spot would
leave a stale never-to-be-used value.  I went with the rename because it was
what should have been done in 2010 or whenever the migration started.  AFAICT,
if someone is paying attention to this histogram, they aren't doing much about
it, and even if I added separate histograms, we'd still be seeing data on the
original histogram until it idles out, so the gain would be minimal, IMHO.

     // Add new entries in the same order as DiagnosticsTestId.
 };
 
@@ -100,8 +101,9 @@ std::string GetTestDescription(DiagnosticsTestId id) {
   TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_HISTORY_TEST);          \
   TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_NSS_CERT_TEST);         \
   TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_NSS_KEY_TEST);          \
-  TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_THUMBNAILS_TEST);       \
-  TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_WEB_DATA_TEST)
+  TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_FAVICONS_TEST);         \
+  TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_WEB_DATA_TEST);         \
+  TEST_CASE(name, DIAGNOSTICS_SQLITE_INTEGRITY_TOPSITES_TEST);
 
 void RecordUMARecoveryResult(DiagnosticsTestId id, RunResultMetrics result) {
   const std::string name("Diagnostics.Recovery." +