[Sync] Erase sync DB when corrupted

sync/syncable/directory.cc

Index: sync/syncable/directory.cc
diff --git a/sync/syncable/directory.cc b/sync/syncable/directory.cc
index 767b80770fc7a1d39ae9560caf8938023e2aafed..0f680d22ec50eaf0b9f62d5ba4a6e3910f09af6e 100644
--- a/sync/syncable/directory.cc
+++ b/sync/syncable/directory.cc
@@ -111,12 +111,12 @@ Directory::Directory(
     : kernel_(NULL),
       store_(store),
       unrecoverable_error_handler_(unrecoverable_error_handler),
-      report_unrecoverable_error_function_(
-          report_unrecoverable_error_function),
+      report_unrecoverable_error_function_(report_unrecoverable_error_function),
       unrecoverable_error_set_(false),
       nigori_handler_(nigori_handler),
       cryptographer_(cryptographer),
-      invariant_check_level_(VERIFY_CHANGES) {
+      invariant_check_level_(VERIFY_CHANGES),
+      weak_ptr_factory_(this) {
 }
 
 Directory::~Directory() {
@@ -208,6 +208,12 @@ DirOpenResult Directory::OpenImpl(
   if (!SaveChanges())
     return FAILED_INITIAL_WRITE;
 
+  // Now that we've successfully opened the store, install an error handler to
+  // deal with catastrophic errors that may occur later on. Use a weak pointer
+  // because we cannot guarantee that this Directory will outlive the Closure.
+  store_->SetCatastrophicErrorHandler(base::Bind(
+      &Directory::OnCatastrophicError, weak_ptr_factory_.GetWeakPtr()));
+
   return OPENED;
 }
 
@@ -1554,6 +1560,12 @@ void Directory::GetAttachmentIdsToUpload(BaseTransaction* trans,
                       std::back_inserter(*ids));
 }
 
+void Directory::OnCatastrophicError() {
+  ReadTransaction trans(FROM_HERE, this);
+  OnUnrecoverableError(&trans, FROM_HERE,
+                       "Catastrophic error detected, Sync DB is unrecoverable");
+}
+
 Directory::Kernel* Directory::kernel() {
   return kernel_;
 }