Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/map_field.cc

Index: third_party/protobuf/src/google/protobuf/map_field.cc
diff --git a/third_party/protobuf/src/google/protobuf/map_field.cc b/third_party/protobuf/src/google/protobuf/map_field.cc
index eddc95c4cac2e8db38aca49ca2a3fb711bd17d4e..49f918181fcc968e46266eec3799c0ba4aa0ec55 100644
--- a/third_party/protobuf/src/google/protobuf/map_field.cc
+++ b/third_party/protobuf/src/google/protobuf/map_field.cc
@@ -178,18 +178,19 @@ bool DynamicMapField::ContainsMapKey(
   return iter != map.end();
 }
 
-bool DynamicMapField::InsertMapValue(
+bool DynamicMapField::InsertOrLookupMapValue(
     const MapKey& map_key, MapValueRef* val) {
-  bool result = false;
-
-  MapValueRef& map_val = (*MutableMap())[map_key];
-  // If map_val.data_ is not set, it is newly inserted by map_[map_key].
-  if (map_val.data_ == NULL) {
-    result = true;
+  // Always use mutable map because users may change the map value by
+  // MapValueRef.
+  Map<MapKey, MapValueRef>* map = MutableMap();
+  Map<MapKey, MapValueRef>::iterator iter = map->find(map_key);
+  if (iter == map->end()) {
+    // Insert
+    MapValueRef& map_val = (*map)[map_key];
     const FieldDescriptor* val_des =
         default_entry_->GetDescriptor()->FindFieldByName("value");
     map_val.SetType(val_des->cpp_type());
-    // Allocate momery for the inserted MapValueRef, and initialize to
+    // Allocate memory for the inserted MapValueRef, and initialize to
     // default value.
     switch (val_des->cpp_type()) {
 #define HANDLE_TYPE(CPPTYPE, TYPE)                              \
@@ -216,9 +217,13 @@ bool DynamicMapField::InsertMapValue(
         break;
       }
     }
+    val->CopyFrom(map_val);
+    return true;
   }
-  val->CopyFrom(map_val);
-  return result;
+  // map_key is already in the map. Make sure (*map)[map_key] is not called.
+  // [] may reorder the map and iterators.
+  val->CopyFrom(iter->second);
+  return false;
 }
 
 bool DynamicMapField::DeleteMapValue(const MapKey& map_key) {