Prevent leaking PDF data cross-origin

BUG=520422

Review URL: https://codereview.chromium.org/1311973002

Cr-Commit-Position: refs/heads/master@{#345267}
void OutOfProcessInstance::PreviewDocumentLoadFailed() {
  UserMetricsRecordAction("PDF.PreviewDocumentLoadFailure");
  if (preview_document_load_state_ != LOAD_STATE_LOADING ||
      preview_pages_info_.empty()) {
    return;
  }

  preview_document_load_state_ = LOAD_STATE_FAILED;
  preview_pages_info_.pop();

  if (!preview_pages_info_.empty())
    LoadAvailablePreviewPage();
}

void OutOfProcessInstance::PreviewDocumentLoadFailed() {
  UserMetricsRecordAction("PDF.PreviewDocumentLoadFailure");
  if (preview_document_load_state_ != LOAD_STATE_LOADING ||
      preview_pages_info_.empty()) {
    return;
  }

  preview_document_load_state_ = LOAD_STATE_FAILED;
  preview_pages_info_.pop();

  if (!preview_pages_info_.empty())
    LoadAvailablePreviewPage();
}
