Delete unneeded pending entries in DidFailProvisionalLoad to prevent a spoof.

BUG=280512
BUG=278899
TEST=See bug for repro steps.

Review URL: https://chromiumcodereview.appspot.com/23978003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222146 0039d316-1c4b-4281-b951-d872f2087c98
void NavigationControllerImpl::PruneAllButVisible() {
  PruneAllButVisibleInternal();

  DCHECK_NE(-1, last_committed_entry_index_);

  NavigationEntryImpl* entry =
      NavigationEntryImpl::FromNavigationEntry(GetActiveEntry());
  web_contents_->SetHistoryLengthAndPrune(
      entry->site_instance(), 0, entry->GetPageID());
}

void NavigationControllerImpl::PruneAllButVisible() {
  PruneAllButVisibleInternal();

  DCHECK_NE(-1, last_committed_entry_index_);

  NavigationEntryImpl* entry =
      NavigationEntryImpl::FromNavigationEntry(GetActiveEntry());
  web_contents_->SetHistoryLengthAndPrune(
      entry->site_instance(), 0, entry->GetPageID());
}
