Speculative fix for bug 37709. Don't use a MutableEntry (and hence add something to the transaction's originals_ array) in apply updates until we know it's a safe type.

BUG=37709,36822

Review URL: http://codereview.chromium.org/705001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@41065 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 5 insertions, 4 deletions

diff --git a/chrome/browser/sync/engine/update_applicator.cc b/chrome/browser/sync/engine/update_applicator.cc
index 268de4c..bcab9d4 100644
--- a/chrome/browser/sync/engine/update_applicator.cc
+++ b/chrome/browser/sync/engine/update_applicator.cc
@@ -50,13 +50,14 @@ bool UpdateApplicator::AttemptOneApplication(
     // Clear the tracked failures to avoid double-counting.
     conflicting_ids_.clear();
   }
-  syncable::MutableEntry entry(trans, syncable::GET_BY_HANDLE, *pointer_);
 
-  if (SkipUpdate(entry)) {
+  syncable::Entry read_only(trans, syncable::GET_BY_HANDLE, *pointer_);
+  if (SkipUpdate(read_only)) {
     Advance();
     return true;
   }
 
+  syncable::MutableEntry entry(trans, syncable::GET_BY_HANDLE, *pointer_);
   UpdateAttemptResponse updateResponse =
       SyncerUtil::AttemptToUpdateEntry(trans, &entry, resolver_);
   switch (updateResponse) {
@@ -84,7 +85,7 @@ void UpdateApplicator::Advance() {
   *pointer_ = *end_;
 }
 
-bool UpdateApplicator::SkipUpdate(const syncable::MutableEntry& entry) {
+bool UpdateApplicator::SkipUpdate(const syncable::Entry& entry) {
   ModelSafeGroup g =
       GetGroupForModelType(entry.GetServerModelType(), routing_info_);
   if (g != group_filter_)
diff --git a/chrome/browser/sync/engine/update_applicator.h b/chrome/browser/sync/engine/update_applicator.h
index 7a412e8..7073f0a 100644
--- a/chrome/browser/sync/engine/update_applicator.h
+++ b/chrome/browser/sync/engine/update_applicator.h
@@ -54,7 +54,7 @@ class UpdateApplicator {
 
  private:
   // If true, AttemptOneApplication will skip over |entry| and return true.
-  bool SkipUpdate(const syncable::MutableEntry& entry);
+  bool SkipUpdate(const syncable::Entry& entry);
 
   // Adjusts the UpdateIterator members to move ahead by one update.
   void Advance();