Revert 110177 - Sync: Improve handling of database load failures

chrome/browser/sync/syncable/directory_backing_store.cc

Index: chrome/browser/sync/syncable/directory_backing_store.cc
===================================================================
--- chrome/browser/sync/syncable/directory_backing_store.cc	(revision 110181)
+++ chrome/browser/sync/syncable/directory_backing_store.cc	(working copy)
@@ -236,11 +236,7 @@
 bool DirectoryBackingStore::CheckIntegrity(sqlite3* handle, string* error)
     const {
   sqlite_utils::SQLStatement statement;
-  if (SQLITE_OK !=
-      statement.prepare(handle, "PRAGMA integrity_check(1)")) {
-    *error = sqlite3_errmsg(handle);
-    return false;
-  }
+  statement.prepare(handle, "PRAGMA integrity_check(1)");
   if (SQLITE_ROW != statement.step()) {
     *error =  sqlite3_errmsg(handle);
     return false;
@@ -293,7 +289,37 @@
 
 bool DirectoryBackingStore::BeginLoad() {
   DCHECK(load_dbhandle_ == NULL);
-  return OpenAndConfigureHandleHelper(&load_dbhandle_);
+  bool ret = OpenAndConfigureHandleHelper(&load_dbhandle_);
+  if (ret)
+    return true;
+  // Something's gone wrong. Nuke the database and try again.
+  using ::operator<<;  // For string16.
+  LOG(ERROR) << "Sync database " << backing_filepath_.value()
+             << " corrupt. Deleting and recreating.";
+  file_util::Delete(backing_filepath_, false);
+  bool failed_again = !OpenAndConfigureHandleHelper(&load_dbhandle_);
+
+  // Using failed_again here lets us distinguish from cases where corruption
+  // occurred even when re-opening a fresh directory (they'll go in a separate
+  // double weight histogram bucket).  Failing twice in a row means we disable
+  // sync, so it's useful to see this number separately.
+  int bucket = failed_again ? 2 : 1;
+#if defined(OS_WIN)
+  UMA_HISTOGRAM_COUNTS_100("Sync.DirectoryOpenFailedWin", bucket);
+#elif defined(OS_MACOSX)
+  UMA_HISTOGRAM_COUNTS_100("Sync.DirectoryOpenFailedMac", bucket);
+#else
+  UMA_HISTOGRAM_COUNTS_100("Sync.DirectoryOpenFailedNotWinMac", bucket);
+
+#if defined(OS_CHROMEOS)
+  UMA_HISTOGRAM_COUNTS_100("Sync.DirectoryOpenFailedCros", bucket);
+#elif defined(OS_LINUX)
+  UMA_HISTOGRAM_COUNTS_100("Sync.DirectoryOpenFailedLinux", bucket);
+#else
+  UMA_HISTOGRAM_COUNTS_100("Sync.DirectoryOpenFailedOther", bucket);
+#endif  // OS_LINUX && !OS_CHROMEOS
+#endif  // OS_WIN
+  return !failed_again;
 }
 
 void DirectoryBackingStore::EndLoad() {