getSelectedContent_(req, sendResponse) {
    if (req.enableLookingGlass) {
      this.startGlassListener_();
    }

    var origin = this.getOrigin_();

    this.api_.getSelectedContent(
        function(recipients, msgBody, canInject, msgSubject) {
          var selectionBody = e2e.openpgp.asciiArmor.extractPgpBlock(msgBody);
          var action = utils.text.getPgpAction(selectionBody);
          // Correct action for draft and reply-to messages.
          if (e2e.openpgp.asciiArmor.isDraft(selectionBody) ||
              (recipients.length > 0 &&
               action == constants.Actions.DECRYPT_VERIFY)) {
            action = constants.Actions.ENCRYPT_SIGN;
          }
          // Send response back to the extension.
          var response = /** @type {e2e.ext.messages.BridgeMessageRequest} */ ({
            selection: selectionBody,
            recipients: recipients,
            action: action,
            request: true,
            origin: origin,
            subject: msgSubject,
            canInject: Boolean(canInject),
            canSaveDraft: Boolean(canInject)
          });
          sendResponse(response);
        },
        goog.bind(this.errorHandler_, this, sendResponse));
  }
Retrieves OpenPGP content selected by the user.
@param {!e2e.ext.messages.GetSelectionRequest} req The request to get the
    user-selected content.
@param {function(e2e.ext.messages.BridgeMessageRequest)|function(Error)}
    sendResponse Function sending back the response.
@private