Coverity: Fixing pass by value.
CID=101462, 101458, 101437, 101471, 101467

BUG=NONE
TEST=NONE

Review URL: http://codereview.chromium.org/9006023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@115257 0039d316-1c4b-4281-b951-d872f2087c98
void ExtensionPrefs::UpdatePageOrdinalMap(const StringOrdinal& old_value,
                                          const StringOrdinal& new_value) {
  if (new_value.IsValid())
    ++page_ordinal_map_[new_value];

  if (old_value.IsValid()) {
    --page_ordinal_map_[old_value];

    if (page_ordinal_map_[old_value] == 0)
      page_ordinal_map_.erase(old_value);
  }
}

void ExtensionPrefs::UpdatePageOrdinalMap(const StringOrdinal& old_value,
                                          const StringOrdinal& new_value) {
  if (new_value.IsValid())
    ++page_ordinal_map_[new_value];

  if (old_value.IsValid()) {
    --page_ordinal_map_[old_value];

    if (page_ordinal_map_[old_value] == 0)
      page_ordinal_map_.erase(old_value);
  }
}
