Introduce the plumbing necessary to report Unrecoverable error from model safe workers.

chrome/browser/sync/syncable/syncable.cc

Index: chrome/browser/sync/syncable/syncable.cc
diff --git a/chrome/browser/sync/syncable/syncable.cc b/chrome/browser/sync/syncable/syncable.cc
index 9038240974bbb63648be871679cb2e464fed778a..2511610578f795362125171e18b4f13442aa62a4 100644
--- a/chrome/browser/sync/syncable/syncable.cc
+++ b/chrome/browser/sync/syncable/syncable.cc
@@ -41,6 +41,7 @@
 #include "net/base/escape.h"
 
 namespace {
+
 enum InvariantCheckLevel {
   OFF = 0,
   VERIFY_IN_MEMORY = 1,
@@ -51,7 +52,8 @@ static const InvariantCheckLevel kInvariantCheckLevel = VERIFY_IN_MEMORY;
 
 // Max number of milliseconds to spend checking syncable entry invariants
 static const int kInvariantCheckMaxMs = 50;
-}  // namespace
+
+}  // namespace.
 
 using std::string;
 
@@ -425,7 +427,8 @@ Directory::Kernel::~Kernel() {
   delete metahandles_index;
 }
 
-Directory::Directory() : kernel_(NULL), store_(NULL) {
+Directory::Directory() : kernel_(NULL), store_(NULL),
+                        unrecoverable_error_(false) {
 }
 
 Directory::~Directory() {
@@ -696,6 +699,8 @@ void Directory::TakeSnapshotForSaveChanges(SaveChangesSnapshot* snapshot) {
 }
 
 bool Directory::SaveChanges() {
+  if (unrecoverable_error_)
+    return true;
   bool success = false;
   DCHECK(store_);
 
@@ -1117,6 +1122,14 @@ void Directory::RemoveTransactionObserver(TransactionObserver* observer) {
   kernel_->observers->RemoveObserver(observer);
 }
 
+void Directory::set_unrecoverable_error() {
+  unrecoverable_error_ = true;
+}
+
+bool Directory::unrecoverable_error() const {
+  return unrecoverable_error_;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // ScopedKernelLock
 
@@ -1157,6 +1170,10 @@ BaseTransaction::BaseTransaction(const tracked_objects::Location& from_here,
       &TransactionObserver::OnTransactionStart, from_here_, writer_);
 }
 
+void BaseTransaction::set_unrecoverable_error() {
+  directory_->set_unrecoverable_error();
+}
+
 BaseTransaction::~BaseTransaction() {
   dirkernel_->observers->Notify(
       &TransactionObserver::OnTransactionEnd, from_here_, writer_);
@@ -1282,6 +1299,8 @@ void WriteTransaction::NotifyTransactionComplete(
 WriteTransaction::~WriteTransaction() {
   const ImmutableEntryKernelMutationMap& mutations = RecordMutations();
 
+  if (directory_->unrecoverable_error())
+    return;
   if (OFF != kInvariantCheckLevel) {
     const bool full_scan = (FULL_DB_VERIFICATION == kInvariantCheckLevel);
     if (full_scan)
@@ -1485,8 +1504,7 @@ bool MutableEntry::PutIsDel(bool is_del) {
   if (!is_del)
     // Restores position to the 0th index.
     if (!PutPredecessor(Id())) {
-      // TODO(lipalani) : Propagate the error to caller. crbug.com/100444.
-      NOTREACHED();
+      return false;
     }
 
   return true;